I used to avoid anyone with -ve trust, I hardly quote them or reply their quotes and they were somewhat few then.
You should keep them separate; engaging in discussion & trading. Feedback is a sign of how much trusted a user can be while engaging in discussion is somewhat else. I don't mind hearing, replying to people who put quality into their posts regardless of their feedback. I guess you can't deny that Quickseller is a good quality poster but he has a lot of negative feedback; that doesn't mean you should avoid them.
I think you're just seeing clusters of shitposters for 1xbit or some other shady campaign or members of an alt ring that got busted; I don't think the level of tagging has increased drastically over the last few months or even years (though I could be wrong, as I have no data on that).
Most likely but in recent days, negative tagged accounts are also accepted in different signature campaigns depending on the legitimacy of the feedback. Apart from that, the number of active signature campaigns has increased significantly in comparison to the last 2 years I have observed. That can be another reason probably.