They tend to be top or above average performers who don't like when co-workers who are sub par are treated and rewarded as their equals.
I have met many sub-par workers who love to throw around the word "toxic" to define and attack such people. I have seen such "rude" or "toxic" people work fine along other exceptional and/or capable co-workers and reject those who cant perform.
"He/she is an #@$hole... but he/she is doing most the work and objectively in the end they are not wrong in anything they have said." Are words I have heard echoed across so many different leadership meetings at various companies.
The Pareto principle is very real in terms of workforce and what we should really discuss is how we can focus on honest constructive conversations that allow the successful to succeed and give critical feed back to those who arent.