I mean, when people move in to a majority black or brown neighborhood they're accused of gentrification. I don't see why this is any different. Elderly people are also vulnerable populations.

May I request you to please cut and paste the part of the parent which I might have misunderstood?

This is the parent, afaict:

[..] notJim 2 hours ago | undown | parent | flag | favorite | on: California’s housing crisis: how a bureaucrat push...

Also a homeowner, and I'm a YIMBY (or PHIMBY) for selfish reasons as well. My neighborhood is mostly old white people, because they bought their houses years ago and stayed put. Not that I have anything against them, but I'd love to have a more diverse, younger neighborhood. More neighbors also means more customers for local businesses, which means more shops and restaurants in walking distance. More neighbors would eventually also mean better public transit, because the ridership would demand it. I think the selfish benefits of more housing are often overlooked due to fear of change.[..]

You could absolutely have more diversity by simply adding people, rather than displacing or removing anyone, which is precisely what the comment suggested.

Sure. You can add people. IF they can afford to buy in. Clearly they can’t...that’s not the problem of existing homeowners who aren’t ‘diverse’ enough for the younger generation.

The entire YIMBY point is to allow more dense housing, so that you can in fact move more people into an area to increase diversity, rather than relying on certain populations to get excluded.

You can’t increase density without decreasing the quality of life by apportioning more of fixed or shrinking resources.