The OP wrote: "Sure, itβs 80% Chinese American, but [it's cheaper]". That made me wonder too why the ethnicity would be a drawback.
An example of how this plays out is demonstrated in the article itself. The author says '80% asian-american' rather than 'asian neighborhood.'
From a political correctness perspective, people in the US don't want to be seen perpetuating anything that could be considered a form of segregation. Simultaneously it is considered negative to be seen as 'gentrifying' a neighborhood, i.e. disrupting the traditional demographics of a neighborhood.
I do think separating culture from race is dodging half the conversation, but I can't argue with your observation that this is the reality of how most people in the area think. Thanks for the feedback.
Generally stereotypes as a concept are considered inherently pejorative in the USA.
Secondly, your inference that people are avoiding the neighborhood is because of the local population. People aren't avoiding the area, the neighborhood is mostly staying the same. Large numbers of people moving into a neighborhood is the exception to the norm. Particularly in San Francisco where there are protections on existing residents such as rent control.
Thirdly, in the USA we would view asian-american as a cultural description, or nationality description, rather than as a racial description. When someone says 'asian grocery store' they don't typically mean 'because asian people shop there,' but a place where foods sold in asia are more available. This point of view would be particularly so in the bay area worldview. In the USA, it is generally considered offensive/patronizing to compliment people based on their race for any reason. People want to be recognized for their abilities on an individual level, or because of some meritocratic reason.
I could go on, but the other reasons are more or less permutations of the above.