1) All of my experiences related to unions have been negative. Things become more bureaucratic and inefficient ("oh no, you can't move that box, we need to wait for the union person whose job description is to move the box"), people are promoted because of seniority and not because of merit, bad performers up to and including flagrant criminals can't be fired because the union would rally to support them no matter how in the wrong they are, etc.
2) FAANG-type jobs have to be the cushiest jobs around. I mean, look at http://levels.fyi. Who else gets paid that kind of money right out of college, for doing a very comfortable office job, with a ton of perks on top?
I get that unions might be necessary in industries where workers are actually exploited, to protect said workers. But FAANG engineers are pretty much in the opposite situation. I don't like people creating an us-vs-them situation that doesn't exist, just so they can promote their own politics. As I commented recently, if you don't like it, quit (https://news.ycombinator.com/item?id=21636860), and let the people who go to work to, you know, do work, do it in peace.