Anecdotally I think it's pretty common for mechanics to claim that their competitors don't know what they're doing.
It kind of makes sense actually, of course I hear of more developers being hostile to other developers compared to say mechanics, but that could be because I hear from more developers full stop. There's probably a term for it and everything.
That being said, I'm sure I've come across a lot more camaraderie amongst other professions than developers. Anecdotally, I know theres been a few times I've complained about or seen people complain about a certain profession and seen a wave of posts come in from other workers defending them. Then again, its possible those just stick out in my mind more than the many times that presumably hasn't happened.