Gerald SoThere was backlash to #Batman / #BruceWayne and #Batgirl / #BarbaraGordon having sex in #TheKillingJoke Movie, but years earlier, in the #BatmanBeyond episode "Out of the Past," #TaliaAlGhul finds elderly Bruce looking longingly at a decades-old, smiling image of him and Barbara. Talia says she knew Bruce and Barbara had been in love. I don't recall backlash to that.
I understand the backlash to #TheKillingJoke #Movie #SexScene. It was part of a prologue added to expand on the story from the comics and make the movie financially worthwhile. The scene didn't work by itself, but it makes sense in the context of #BruceWayne and #BarbaraGordon eventually developing a committed romantic relationship, not an isolated incident of Barbara breaking their sexual tension, that didn't lead anywhere serious.