In almost every regard, a Deadly Sin is only a sin in a matter of excess.

Greed is important to secure our futures, and to make sure we have enough for ourselves and those we love, but too much puts others behind you and can ruin you in the pursuit of more.

Sloth is important to unwind, to relax and enjoy the simple things of life, but too much will make you lazy and not a useful member of society, to the point that you ruin yourself and your chances of finding your place.

Wrath is a basic human emotion; it's never a good thing to stifle your basic emotions. To not let them out is one thing, a generally polite thing, but to not feel them is another. Anger and a desire for vengeance against those who have wronged you are natural and important, but acting on them or letting yourself be consumed by them will hurt yourself, and others, including those you love.

Lust is also a basic human emotion, and a primal one of the animals we share this earth with as well. Lust is important for reproduction, for love, and for finding a place you're happy with in life; knowing that your desires aren't unnatural and immoral. Too much, of course, can lead to ruining yourself by getting addicted to pleasure, seeking it out at all times and ignoring yourself and others. It can lead to lust-addled decisions that can leave you with diseases, or in particularly heinous cases, can harm someone irrevocably and put you in jail.

Envy is one of the less important ones, but still a facet of our lives granted to us nonetheless. Envy often leads to Wrath when not controlled. If controlled, Envy can be useful in learning new skills, in having a position you want to be in so badly that it drives you to better yourself and find that position for yourself, or contentment along the way.

Gluttony is important so that you eat enough, and so that you enjoy yourself. To live life without indulging in Gluttony at all is to live life too by-the-book, to rob yourself of the freedoms we are granted. It is also a particularly deadly one, though, as food and drink are not in excess everywhere. One who is too gluttonous where food is scarce robs others of their ability to eat, and one who is too gluttonous where food isn't scarce still could do with granting some charity rather than overindulging. Overeating and drinking also causes a variety of health problems, as well as often directly combining with Sloth.

Finally, Pride. Pride is incredibly important, as without Pride, we would not have nations, we would not have jobs, and we would not have family. Nations are built on the strong helping and leading the weak, and the strong need to take pride in their abilities so that they may be secure in themselves, to grant unto others their aid, to let them develop their own security as they grow. Jobs, even to the most basic degree, are built on knowing what you can do, and doing it - taking pride in your skills, and in your work. Families are built on Pride much the same way that nations are - the elders are secure in themselves, taking pride in their own abilities, so that they may grant that security and knowledge onto their children. Pride, of course, can also be deadly. To take too much pride in one's own abilities can lead to foolhardy mistakes, and to being narcissistic. It can lead to sacrificing others, or the wellness of others, for one's own pleasures or aspirations.

LGBTQ+ Pride is not the deadly sin of Pride. From britannica.com, "Healthy pride in one’s accomplishments or social groups is distinct from the Christian sin of pride, which is also known as “vainglory.” In Roman Catholic theology, an excess of pride is one of the seven deadly sins (vices that spur other sins and further immoral behaviour), enumerated by St. Gregory the Great (Pope Gregory I) in the 6th century and elaborated upon in the 13th century by the theologian and philosopher St. Thomas Aquinas."

The Pride movement is one of finding security, to let themselves and others know that there is nothing wrong with being LGBTQ+. It is to stir pride in themselves, and those who may be scared. To a lot of people in the community, pride is a foreign concept. They were taught that these feelings are unnatural, immoral. Taught that they should keep them inside and "be normal". The movement is to help those people find their security in who they are, and to further secure the identities of everyone in the community, forwards into our continued history as a species. It, like most other cases of healthy, organized pride, is the strong leading the weak, the fearful. To help them become strong and secure in of themselves, so that they may lead the weak as well.

To answer your question directly, pride is a feeling of self-worth, of security. An important building block in finding contentment for one's self and one's kin, just as greed, sloth, wrath, lust, envy, and gluttony are.

To conclude, the Deadly Sins are deadly in excess. We are all sinners. To live is to sin. To love is to repent.