Is Lemmy.world a cover for Liberalism, because it’s run by liberals? Is db0 a cover for Anarchism and Libertarian Socialism, because db0 is a Libertarian Socialist?
Liberals and libertarian socialists are usually pretty open about what they believe, so there's no cover needed. They're not fringe ideologies like tankies have.
However neoliberalism is a fairly hated ideology. If the people who ran lemmy.world were literally the same people running a neoliberalism sub on that instance and they also ran thatcher.love or whatever, and they banned people for saying neoliberalism was trash, then yeah, it would be a reasonable inference that lemmy.world was some sort of entryist ploy.
It is the existence of lemmygrad combined with the behaviour of the people running lemmy.ml that makes the case to defederate. If that happens and you don't like it, you could always migrate your account, unless you like it there, in which case you're probably not the normie you first appeared to be.