Web devs specifically seem to be especially prone to inheriting biases from more senior devs that they've worked with, to the point that they spout things like "php is terrible and no one should use it" or "jquery is bloated and useless" without actually having used the technology they're rallying against. Or sometimes they'll maybe have messed around with a poorly written legacy application, or they'll go through a tutorial.

I actually partially blame xkcd for people spontaneously getting these kind of trendy opinions. If I had a nickel for every time a junior dev quoted that 99 problems regex comic to my I'd have like... a few bucks.

Things are outdated when they no longer have use do to their age, they aren't outdated just because there's something shinier.