Same reason he wrote it in the first place: he's drafting off a trending topic to gain exposure and hopefully new developers.
Write one letter to the Diaspora team and, at best, they consider it. Put the letter out there (under the guise of being related to Diaspora to gain extra attention) and maybe a dozen teams consider it.
Because it's impossible to start working on a FOSS project in a field without the people behind the various failed, embryonic, or plain poor pre-existing projects in that field demanding that you instead validate their work.
Yeah I realize why one would write an open letter like this. I guess I was just complaining about taking this approach. Seems like a thinly veiled attempt at drawing attention to their product and nothing more.
Write one letter to the Diaspora team and, at best, they consider it. Put the letter out there (under the guise of being related to Diaspora to gain extra attention) and maybe a dozen teams consider it.