I think there's more than one kind of language snob out there. Some of them have never programmed in more than one language, and so naturally think that language is the best. Some don't regularly program in any language, and take whatever fad du jour is on Reddit as gospel. But others have programmed in lots of languages, and have tried the languages in question, and that's why they think it sucks.

It can be difficult to tell them apart. But one way is to look at the depth of their criticisms, and how many of those criticisms you've heard before. If they say the same things everyone else says, chances are they're talking out of their ass. But if they can come up with unique, detailed, insightful reasons why a particular language sucks, it's pretty likely that they've used it extensively and have some idea what they're talking about.