most 'classic' conspiracy theories — positing huge implausible covert webs of influence behind seemingly disparate events and groups — mostly come from a refusal to commit to class analysis
like obviously the rich and powerful are out to get you — that's capitalism. but when your ideology itself is built on capitalism it becomes cognitively cheaper, so to speak, to instead imagine there's a huge masonic-catholic-jewish alliance behind it all
there is also a lot less of a border between this line of thinking and the idea that there are 'good' and 'bad' forms of capitalism. 'crony capitalism' tends to be 2 or 3 steps removed from outright anti-semitism; because when you imagine there is or was a primal form of 'pure', 'true' capitalism that was corrupted by a nefarious, profit-grabbing element, you might as well go all the way, right
i've said before i don't like the term 'conspiracy theory' because it both implies a unity that doesn't exist (someone who believes the moon is an alien spaceship is unlikely to believe the earth is flat) and hides the way many 'conspiracy theories' are in fact just manifestations of ur-fascism
there's this implicit idea many people have that there is a sort of a slider from normal people who believe in normal things to crazy people who believe in weird things, and everyone at a particular point on the slider believes in the same things. this, obviously, is just another way for liberal ideology to evade scrutiny by laundering itself as natural or self-evident