They have no interest in "property value". Especially if they already have too much money.
NIMBYism is less "I don't want my property value affected" and more "I don't want anything affected"
That's really not generally true. Talk about "property values" generally does actually pertain to financial outcomes related to their property.
And they have valid reasons to: if you're paying a mortgage, you're in trouble if the value of your property drops. Even if you've paid off your mortgage already, you still don't want it to drop, because it reduces your wealth on paper (reducing your financial flexibility), and it also reduces the size of the estate you can bequeath to your children. But more immediately than that: just because the value of your property has dropped, that doesn't mean the taxes you pay on it automatically drop too. (See: Detroit, where people had to sell their homes to force a revaluation, because the annual taxes were more than the value of their homes after the market crashed, and the city refused to reassess the homes, because it was broke).
The problem is that "property values" is also used as a dog-whistle for racism and redlining - or, in other words, making neighborhoods less accessible to (or attractive to) people who aren't white. This is especially true in California and the Pacific Northwest, which has an incredibly long history of passing exclusionary laws regarding housing and property ownership.