I know that it's Chinese and it translates roughly as "white/Western left." Looking it up on the Chinese wiki, Google translate gives me... well, this:
It is used to describe people who support policies such as the abolition of the death penalty , [ 3 ] animal protection , environmental protection , body equality , skin equality , LGBT , feminism , vegetarianism , marijuana decriminalization , euthanasia , abortion and immigration , that is, people with cultural leftist ideas in the European and American world.
This paints baizuo as something akin to American conservative terms like "woke" or "SJW." On the other hand, I've seen baizuo on Hexbear a few times, but in those contexts it seemed to mean something closer to "succdem" or "Western chauvinist" rather than the definition above. Obviously, a term used to insult feminists, LGBT people, and environmentalists would be incredibly out of place on this site, hence why I'm asking about it rather than taking a machine-translated Wiki article at face value.
Ehhhh, when the definitions are so close but the differences are so important that gets a little shaky, because confusing the two definitions is extremely easy. A lot of the context in which I can imagine a hexbear user using the word would make total sense with the more reactionary definition, just as much as with the better and less reactionary one, so it would be easy to misinterpret as more reactionary. And even if everyone involved knows what it means it could open up wiggle room for reactionaries to slip into site discussions, by using the term's plausible deniability to get away with terrible statements.
"Western chauvinistic leftist" or language equivalent is generally just clearer and seems to have less murky and questionable of a background.
Plus some words just inherently emanate Hitler particles. I don't know if this counts as such a word necessarily, but the definition given on this post comes close enough to extremely strange Nazi-Bolshevik brainworms to be uncomfortable. If the term literally is referring to mental capacity and not levels of chauvinism or evil than it is definitely a Hitler particle emanating phrase.
I'm sure your friends mean no harm, it just isn't something I personally think should be given the complete green light to be used. (Here, probably fine in friend contexts and stuff) Maybe like a amber light for caution.