I don't think that is a fair summary of this critique at all.

The author has laid out specific, actionable items, such as putting Signal on F-Droid and allowing federation. Maybe he doesn't like Moxie, but it's not so simple as attacking his character. Instead, this is a reasonable summary of steps Signal can take to win his trust (or, to give him a true impression that he needn't trust it).

I think it's fair.

He accuses Moxie of being deceptive and insincere:

"It can be hard to distinguish these from genuine positions held by the person you’re talking to, but when it conveniently allows them to make self-serving plays, it’s a big red flag."

He then admits it's "a strong accusation". Later he dismisses Moxie's reasonable stance re: federation with "Moxie can write as many blog posts which appeal to wispy ideals and “moving ecosystems” as he wants".

That's not a reasonable critique, that's pure vitriol.

I would love to see federation in Signal, but I can understand why OWS decided otherwise. The author is not able to distinguish between "someone has weighed the issue differently than I would have" and "he's doing that for his own personal gain".