Well, before we get into the moral/immoral dimension, the fact is that these areas are growing from net migration in, rather than internal population increase. So in some sense the huge influx of these new residents (typically with high-paying tech jobs) are pushing out the parents and grandparents (and not bringing their own extended families anyhow). So the atomization of intra-family bonds that seems so immoral to you is actually caused by the migration, driven by underlying economic opportunities and not some NIMBY anti-growth mindset.

> It enriches homeowners at the expense of other's misery.

This is a profoundly subjective view, because homeowners could turn around and accuse new residents of enriching themselves at the expense of homeowners; adding traffic, pollution, destroying nature, maybe bringing crime, increasing population which increases distance and reduces oversight of schools and politics, requiring more police. So a lot of people who want to keep their town small and close knit would disagree with the premise at the outset. Do communities have rights too?