I think the point is they shouldn't qualify. I don't consider MS to be a "FAANG" - I would agree too. Nothing about the company feels like the energy that the other companies bring. They're playing catch-up and while they're huge by market value and impact they're just riding that legacy and to me not really deserving of being part of the "cool kids club" which to me was where FAANG sprung from.
Microsoft didn't spawn Apple. They were siblings, sometimes cooperating and sometimes fierce rivals. Microsoft also bailed out Apple so that it could exist to this day.
Microsoft was the big software giant (well, IBM, but . . .) when Facebook and Netflix and Google got their starts, so ex-'softies likely had an influence on culture and practices in those companies. Amazon is also Seattle-land headquartered and I know there was cross-pollination there.
Even if you think Microsoft is totally crap and not a FAANG, there was some fecal transplant going on with the FAANGs.
Personally I think Microsoft belonged more than Netflix, because Netflix is tiny by comparison. Same reason Twitter never belonged. But if you leave them both out you can get a good acronym.
M(eta)
A(pple)
N(vidia)
G(oogle)
A(mazon) -> MANGA
Yes, it ignores the Google/Alphabet change, but they still seem to be pushing the "Google" brand more than Meta is pushing the "Facebook" brand so I think that's reasonable.
P.S. It also seem rather apropos that they're only one letter away from MAGA.