Because he chooses to feel guilty. No one can make you feel anything without your consent.
I'm with you. I'm a single mom, and by choice. I do not regret my choices. It was a good choice for me. I'm only responsible for my choices. No one else's.
I've never forced anyone to date me. Since men typically ask women out, I'm not sure where this drama about being supposedly "guilted and shamed" do not wanting to deal with children is coming from. Kinda smells like projection of some sort to me.
I've always been glad to know up front a potential suitors thoughts on kids. That way, neither of us are wasting our time.
I have found, that men are purposefully obtuse and obscure on the matter. It's like pulling teeth. I figure it's because they still want sex most of the time. Best case scenario, they've just honestly never thought about it.
Either way, a guy acts like this .... Ditch him quick.