Brown "Asian looking" people can get discriminated against. For example, I live in a marina. I have invited many friends over while I have lived here, and if they were white, they just walk past the guards at the marina gate with a smile and perhaps "i'm going to Axx". But my "brown" american friend (of very mixed heritage! But VERY american) was stopped and grilled. But because she is American, she just hit the roof and they backed off and let her through.... (this was before covid and form filling to enter anywhere!).
So yes. HK is racist. But usually if you stand tall, (particularly, dress well) and push back at it, it seems to just fizzle.
I'm Brown so this might help ... From my experience, HKers aren't racist (Maybe the old generation are but I have limited interaction with them) but they definitely will discriminate based on your social status so dress well and you shall be fine.
The only time I've seen people walk away from me on MTRs are usually the older generation. Normally, I wish people would walk away from me as I hate how crowded MTR gets during peak hours.
Plus I am into cologne so I believe I generally smell inviting
In general the only people who you'll have problems with are the small minority of older ethnic-Chinese locals who are really backwards (and not only with regards to skin color).
A map of the least racist countries in the world... if you want to avoid racism, head for white, English speaking countries.