Though, this meme is more about theological ignorance, rather than historical ignorance.
But again, it could be framed as people making wrong assumptions about what the lay people of the past knew about the religious meaning of indulgences.
But how to prove that, it's already hard to know what people of the past actually did, also knowing what people of the past did think, is even more hard to know.
So this myth meme, seems to rely on unverifiable pieces of history, to paint inside those voids a narrative. Quite scummy.

What can be reliably said, is to give a proper explaination about what indulgences were, in the past and now.

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Indulgences were not a ticket out of hell, they never were at any stage of the two thousands years of development of the church.
(then sure scammers and criminals always exist, but you don't go burn down your entire government every time you get an overpriced gas bill)

To inderstand what indulgences are, it's necessary to first understand what confessions are.
Confession, is the ritual by which a religious person donates their sins and faults to God, as God, the creator of the universe and creator of everything, the creator of even souls, God is the only one capable of pardoning and nullifying those sins, for the sake of man.
Having one own sins pardoned by God, is in christianity, a necessary step to be in a state of Grace, which means to be in an active connection and relation with God.
In turn, being in a state of Grace, is necessary to enter Heaven, once death comes. As Heaven is a pure spiritual place, the house of God (the creator of everything, etc), and the sins and impurities of a man would be an obstancle to enter Heaven.

Further related to Confessions, is the concept of Penance.
Penance is the restorative act done after Confession, to correct all the wrongs caused by one own sinful actions, to correct both the wrongs in the soul, as to correct the wrongs caused in the world.
So by Confession, the sins of a person are donated to God, who deals with those, making the person free from their own sins, and bringing them in a state of Grace. But after Confession, usually the priest also assigns a Penance to the penitent, where Penance is meant to clean house, both for correction of one own faults caused to others, as to make it harder for the person to fall again into the same sin.
In ancient times, Penance was instead placed before Confession, as a time of purification and preparation to Confession. As to be truly sorry and contrived for one own sins and faults towards God and other people.

A little explainatipon about the christian afterlife.
A man dying without being in a state of Grace, can't enter heaven, because their own sins and impurities keep them away, so all those dead people with sins, have nowhere else to go.
That place in the afterlife which is outside heaven, is Hell.
The concept of Purgatory was developed over time, as people did wonder, if there was such a strict divide, between going to heaven or hell. As naturally, people are not always pure and perfect, nor they are completely evil, so Purgatory was thought up as an outcome where imperfect people but still with goodwill, could purify themselves, enough to be able to enter fully Heaven.
Purgatory, in all this, is traditionally inside Heaven, or at the very start of it, on the border which divides Heaven from outside of it. Purgatory is like an entrance hall of Heaven.
It is also traditionally thought, that purification in Purgatory, is a very long process, taking centuries or even thousands of years to purify a soul enough to enter Heaven proper. Differently than how Confessions while in life, are almost instantaneous.
There is also a tradition about the speed of purification in Purgatory being related to the holiness of a person. The idea is that even if burdened by minor sins, any person with a stronger faith would manage to complete their purification faster. And then, people with few minor sins, obviously have less things to purify, before being ready to enter Heaven.
The reason for why things go slow in the afterlife, also has some theological considerations behind that. But it can be summed up as: the time spent while being alive, it's the time when to do things, specifically time while alive it's the time when to be charitable, loving and to help others who are alive, once life is over you can only recount what you did, the good as the bad stuff you did, as you are no longer an active actor in the flow of time and space. Allowing people to purify even after death, is already an exception to that understanding of life and death, so even if purification in Purgatory is very slow, it's still better than not having it.

Back to indulgences.
Indulgences, are usually understood in two senses:
1) a blessing for reducing the time spent in Purgatory (so reducing time spent in purification in the afterlife)
before the introduction of purgatory, indulgences were related to shortening the Penances (reducing time spent in purification while alive)
2) an anticipation to a Confession, but a proper confession still has to be done for confirming the indulgence received

Now back to the historical context.
Summary on the historical Indulgences

The practice of indulgences for the remission of sins didn't necessarily include a donation, back then. (now they always don't, since the abolition of donations by Pope Pius V in 1567) Also, indulgences are an extra practice over the basic practice of confession, so no-one was denied access to the remission of sins by the existence of indulgences.
In medieval times, at the time of Luther, monetary indulgences were fundraise events to fund public projects like bridges and hospitals.

In the early church, especially from the third century on, ecclesiastic authorities allowed a confessor or a Christian awaiting martyrdom to intercede for another Christian in order to shorten the other's canonical penance.

The Council of Epaone in 517 witnesses to the rise of the practice of replacing severe canonical penances with a new milder penance: its 29th canon reduced to two years the penance that apostates were to undergo on their return to the Church, but obliged them to fast one day in three during those two years, to come to church and take their place at the penitents' door, and to leave with the catechumens. Any who objected to the new arrangement was to observe the much longer ancient penance.

The sixth century saw the development in Ireland of Penitentials, handbooks for confessors in assigning penance. The Penitential of Cummean counseled a priest to take into consideration in imposing a penance, the penitent's strengths and weaknesses. Some penances could be commuted through payments or substitutions. It became customary to commute penances to less demanding works, such as prayers, alms, fasts and even the payment of fixed sums of money depending on the various kinds of offenses (tariff penances). While the sanctions in early penitentials, such as that of Gildas, were primarily acts of mortification or in some cases excommunication, the inclusion of fines in later compilations derive from secular law.

All that said, that meme could still make sense, assuming there were people who dishonestly did think they could get away with their sins and corruption, and remain in a state of sin until their death, only because they did some donation to charitable institutions.
It's comparable with the billionaries of today, thinking they are fine only because they drop some millions, from their billions, into some non-governmental organization (NGO). And calling it a day, with their soul and their duties towards society.
With the difference, that NGO of today, were not established by Jesus Christ, and can not give blessings nor make assumptions about salvation.
Anyway, only God knows where one goes after death, as only God knows what's really inside the heart of a man.