It's a tumblr drawback, for sure--and one of the reasons I never engage in discussions there outside of the messaging option.

In considering his responses, it's clear how limited his own views are that he thinks a childfree community automatically rejects other choices. My group of friends is almost completely childfree--some by choice, some by circumstance. We all feel good about our situations (and increasingly so as time passes). But if any one of us suddenly decided to have kids, we'd still be supportive. We are friends, not ideological zealots.

He's the one insisting there's a single "correct" viewpoint; he assumes in others what he sees in himself.