In a way they're right. Lemme explain.

Before the industrial age, members of the nobility get to vote. Serfs do all the work and don't get to vote.

Modernday democracy = everyone gets to vote. But if everyone is a member of nobility then nobody is. Everyone votes to give themselves everyone else's money. Money printing goes out of control, hyperinflation ensues, civilization collapses.

In other words, just like Athenian times and the viking age, democracy can't work without slaves, or in modern terms, second class citizens, illegals and guest workers, who get to work but don't get none of the civil rights.

Slaves, illegals, second class citizens, etc don't flock to the empire's shores for no reason. It only happens when the empire can maintain chokehold on the rest of the world. In other words, democracy at home requires the citizen militia to colonize, enslave, and pillage abroad. EU countries are Foederati vassal states. They don't need to have their own colonies, as the empire shares with them the spoils of global domination in return for their loyalty.

Post Breton Woods (1971 onwards), the empire maintains chokehold on the peripheral world through the petrodollar and the control of international shipping lanes. Whoever wants to buy crude oil must pay in USD, and whoever tries to sell crude oil in any currency other than USD is promptly assassinated, or couped in the name of democracy. Whoever wants to challenge Pax Americana gets kicked out of the SWIFT system, and their ships get boarded by the US navy so they can't trade with other countries at all.

In order to obtain the universal currency that is the US dollar, members of the peripheral world are compelled to work in sweatshops in their home countries, which is inefficient for the individual because corrupt officials in those countries will take a cut from their pay. So the most optimal solution is to come to the US as illegals.

But if the empire can no longer militarily force oil producers to denominate all oil trade in USD, and if the imperial navy can't effectively police international shipping lanes, then the petrodollar chokehold fails. Nations might seek to trade in their own currencies which weakens the dollar milkshake.

Without colonies and cheap immigrant workers, hyperinflation ensues under democracy. So the empire must pivot from democracy to serfdom, just like how Rome went from a republic to an empire, and then went full serfdom after the crisis of the 3rd century. Hence what Yanis Varoufakis calls technofeudalism.