Like I said there are fanboys of all of them, and there's definitley backlash against Nintendo. Though a lot of it is backlash against Nintendo fans for being so hyperbolic (with threads like this one as an example), though there are plenty of examples of fanboys of the other two being terrible as well. A good current example is Sony fans defense forcing them blocking crossplay with Fortnite and other games.
But I agree it comes down to your own bias—in my case it's just bias against Nintendo fans. I love a lot of Nintendo games, but can't stand their fanboys more than the others for whatever reason and have a fuckton on ignore and will watch this thread to ID more to block. :D. My real bias is I just fucking LOATHE people with loyalty to corporations. It's not just gaming, just any product. I use Apple products (other than computers) and can't stand Apple's cultish fans. I think that's why the Nintendo fans rub me so much the wrong way— there just seems to be more of a monolithic cult of them like there is for Apple who just think there's something "special" or "magical" about that company itself where as the fanboys of the others are often more fanboys of the big games/franchises moreso rather than just Sony or MS overall (with exceptions of course).
In any case, whatever my bias is I end up with way more Nintendo fanboys on ignore on every site I've ever posted on in 20+ years on forums than any other company despite enjoying Nintendo and having owned every console and portable they've made sans Virtual Boy. *shrugs*
You really have to admire their marketing and user base cultivation. Any company that gets thousands to millions of people unironically saying "it just works" or "their games are magic" deserves all the praise they can get.