Why Netflix questionable?
"FAANG" was an arbitrary wall street label for bunch of stocks that were producing big returns about a decade ago. Netflix happened to be making a ton of money at the time the term was coined, and Microsoft happened not to be, so we got this weird acronym standing for "big tech" that doesn't represent the companies which actually make up Big Tech.
They might not be quite at the scale of Facebook, but they are certainly having an impact on the tech world. They may also be showing that you can have a successful business and not strangely diversify your portfolio just to satisfy the market.