True about the origin of the app, but I really don't think it's meant as an actual compliment.
"connecting people" is what Meta employees tell themselves. Daniel is speaking to the ego of the Meta bosses, the story they tell about themselves, to their lower ranks, and to the rest of the world.
The fact that Meta blocks opportunities to connect therefore goes in the face of the story they tell themselves and to others.
It would've been cooler if he told the true story though, it would've been more devastating, and set Pixelfed apart much more.
I'd call that a very strong character accusation. It's a valid complaint that he missed the actual origins, but I would not venture so far in characterizing a person, if it's based off a single mocking letter.