I think there’s a clear distinction between (1) doing an act because you find it fun in itself, (2) doing an act because it eliminates an unwanted consequence of some other fun act.

When I say no woman gets an abortion “for fun”, I mean there is no woman for whom abortion belongs to (1); when some pro-lifer claims women get abortions “for fun”, they are talking about (2) not (1).

My claim that essentially everyone agrees it is immoral to harm babies for fun is talking about “for fun” in sense (1) not sense (2)

Sure, you can constantly keep making distinctions to insist you're correct. But it's an absurd statement anyway and it has no actual support.