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.
A lot of those issues are in fact only mostly hegemonic in the western left, and even that is a recent thing that I do think it's probably related to how we can't really get anything done with economic issues.
In the rest of the world where life is generally worse it doesn't shock me that other things are prioritized, and in some countries where these issues are used as cudgels by imperial core countries (to condition aid or policy) opposing them passes as an anti-imperialist, or at least pro-sovereignty, cause.
It's also true that someone who supports all these culturally left positions doesn't necessarily support other historically leftists causes like anti-imperialism and anti-militarism (anti-nato), so I guess some chinese people invented a term for that kind of leftist, which, from the outside I guess if you count the "left" very broadly from center-left socdems to progressive liberals it would seem like that's all the "white left" is.