I have clients. I talk shit about them to my co-workers.
I also genuinely like many of them, even the ones I talk shit about. It's possible to both like and also be annoyed or aggravated by someone, especially when it comes a client for business, and obviously stripping is a business too. People can, and often do, have conflicted feelings.
Think of the general stripper web as a women's locker room, and it makes more sense. You're just hearing the worst of it there. A dancer bitching about an ugly, cheap, degenerate PL might have also made a genuine connection with that PL, but she's not going to talk about that in the locker room.
And @PuddyTat69 has a good point here. We shouldn't throw stones from this glass house we're in, there's lots of disrespectful behavior here too.
The best thing for everyone, PLs and dancers alike, is to try to be respectful towards each other, we'll all have more fun that way.