One of the things that we have to remember is that to people of BL's political leanings, liberals aren't left wing at all. The left wing according to actual leftists starts at an acceptance of the need for "the people" (or insert whatever term you prefer) owning/controlling the means of production. So while on most political spectrums (or whatever structure/scale you prefer), social ownership of industry/capital is a fairly extreme left wing ideal (with things like appropriate regulation, strong unions, progressive taxation, minimum/living wage laws, etc in between the extreme left and centrism), it's actually the starting point of leftism, according to leftists. Their scale then progresses further left from that and they generally think that we're the ones arguing around the margins as our ideals start with some form of capitalism at the root.
So he absolutely thinks that liberals are bed fellows with fascists, because actual leftists don't see a whole lot of difference between something like social democracy and nazi germany sans the holocaust. The nationalism and militarism isn't the problem (quite they opposite, leftists are pretty fucking fond of both), it's the capitalism.
It's batshit, but it's what leftists actually believe.