I think regressive leftist is still the best term myself. It isn't a sneer, it isn't a snap, it's simply a descriptive in and of itself. People can easily see if someone who is called that is indeed such.
Compared to SJW, which is, at its core, just the use of a word that has negative connotations now, to the point where the whole 'social justice' part as well as the 'warrior' part are sarcastic snark.