It's getting harder and harder to tell because bot activity has gotten so good, but Matthew Green has been around a while and is a genuine old school crypto dude. There is a group of people who just believes that crypto and privacy are good things and want to promote them.
The reason it gets harder is because you can spin up a handful of "expert" accounts shilling for this or that privacy VPN or bitcoin scam etc. So it's hard to just pull up a list of statements and know whether it has any weight. In this case, Matthew Green has a lot of weight because I've followed him for a while and I know what he's about.