It used to be like that, but these days I often encounter the opposite, with ex-FAANG people having stigma attached to them, though arguably mostly google. FB is I think second in that.
I once applied for a job at medium-sized startup, passed their phone screen, take home assignment and onsite, and then had a meeting with the CTO where I was told that they have had problems with ex-Googlers before, and then was rejected after that conversation.
That seems like a very narrow minded approach. I’d be concerned about applying to that sort of company just by hearing that they apply nonsensical filters like that. Can you give some examples, since you claim there are multiple?
Outside (even more outside USA), and also in terms of workplace environment "feeling" and choice of projects, things get a bit different.
Is there still clout? Yes, definitely. But it stopped being automatic badge of merit, at least according to friends who either work(ed) in FAANG companies, or were on the other side of recruitment involved.