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.
We know they know we're right, though, because they'll tell us when our ideas are separated from the material changes that are required to implement them. Ask a lib what they think of:
You're probably going to get supermajorities on roughly the same page as us, at least when they're speaking in the abstract. They do value many of the things we do.
The problem, of course, is when someone whispers "property values" or "the price of gas" in their ear. Suddenly all those good intentions vanish because it could conceivably be a threat to their own material conditions. We know they know that's wrong, too, because libs lionize people who put what's right over what's profitable.
I don't disagree that they agree with the moral righteousness of any policies (or oppositions) in a vacuum, they just deny that vacuum exists, which they are of course right to do. Take universal healthcare or public housing or anything else, their position is typified by saying "it would be great if we could have this, but we can't, because there would be worse moral tradeoffs if we did". The quintessential examples for this are universal healthcare stifling innovation and immiserating hundreds of thousands of workers.
Now are those objections true? No, but they believe them, and that's how they can see their position as being the more moral of the two.