I upvoted this comment of yours because it seemed kind of unfair to me for it to be downvoted, and I don't like people being told what they can or can't do, but the gist of what you're trying to argue is complete nonsense. GCM dependence is a complete non-issue in context, and to say that because Telegram doesn't have that dependency it is safer from US intelligence is so over the top ridiculous. Signal-the-app has it's problems, and a fair share of questionable decisions, but GCM and Play Store are not among those.
That Moxie acts with contempt toward people on GitHub issues is true. It is also true that most of those people (in exchanges I have read) are complete ignorants who wouldn't know security if it hit them on the head, yet insist and yell with noble indignation that they're correct. The kind of people who were thought that more FOSS = more security is an axiom and go from there. Since he gets tons of that, I kinda understand why he might act like that. I understand, but do not condone, it's extremely off putting. In the end, one of Signal-the-app's biggest problems is that it's mostly criticized by unreasonable people.