Yes, probably the saddest thing I read this week. Self-promotion on twatter and HN is different than forming friendship. The goold old days of fora was way better to make friends from the internet IMO. Nowadays everything seems to be a link aggregator which fundamentally change how people interact with each other.
Also it may be more an academic thing, but cold emailing is a good way to make contact. Not necessarily friends thought it can happen but at least it can make projects advance, with very little (public) noise.