I agree that FAANG engineers aren't necessarily the geniuses they hype themselves out to be, but making broad assertions needs some baseline aside from personal experience as my personal experience with FAANG engineers has been mostly positive. That's not to say non-FAANG engineers aren't competent either, as I have worked with non-FAANG engineers as well and they were perfectly fine.
The intent of the OP was simply to dismiss anyone working at FAANG and insinuate they were all subpar and average. He thinks you can just say "from my experience" and that just absolves him from any criticism of his statements. It's completely disingenous.