YIMBYs in my area are almost exclusively terminally online young adults who are bitter that they can't afford to live precisely where they like with their single 20-something income, and basically want to make desirable areas more affordable (aka less desirable) so they can move in. The worst of them are openly hostile to anyone who made the apparent mistake of choosing to live in an upper income area.

I am pretty much in favor of people being able to do what they want with their properties, as long as they are responsible for any externalities the changes create, and I still largely find these groups insufferable (in case you couldn't tell from the paragraph above).

NIMBYs are mostly people who have other things to do with their day than agitate to make their neighborhood worse (where worse is a change from the status quo, which they presumably are at least okay with given they live in the neighborhood), so you don't hear much from them most of the time.

In short, there is no need for advocacy for the status quo unless someone is attempting to modify it, as it just continues on by default.