Every liberal does it too, from center right radlibs to far-right "conservatives": the most extreme right fringe liberals hate the mainstream liberals for not being bigoted enough, the mainstream libs hate the radlibs for not being cruel enough, and the radlibs hate the left for not being chauvinist enough.
Denouncing chauvinism in particular is like a liberal moral event horizon, a cardinal sin against their self-interested belief in the righteousness of the imperial hegemon that keeps the treats flowing at gunpoint.
I don't know. Look at how much Democrats define themselves by being not Republicans. Hell,
essentially ran on "nothing will fundamentally change [compared to the Obama years]." He was the generic "not Republican" candidate!
On the interpersonal level, it's pretty common to excuse one's own shortcomings with "at least I'm not like that fucking guy," especially if that fucking guy is the only other point of comparison. Imagine you aren't a very good worker but always skate by because the only other employee is even worse. What are your thoughts going to be on a new worker who comes in and does the job even decently?
In the past 50 years there have been only 2 elections where the Democrats had any effective platform besides "we're not that fucking guy".