When I say shown having sex, I mean you see everything. Softcore tends to not actually do it, but it's still called porn. I was actually on the set of a softcore shoot a long time ago. There were plenty of scenes, but no actual sex, and the cast and crew called their movie a porno all day long. Every sex scene the lead actress had, she was wearing black electrial tape over her nipples, and wore pants, so she was never fully nude. If you think that by my definition what you see on broadcast TV and big budget movies is porn, I'd call you a prude. They can imply it, entice you to think of it, but they can't actually show it. Making Memories took it's sweet time getting there, but it was all just set dressing to lead up to a few very explicit sex scenes. It was epic, and had a great pay off. It was still porn. If this game follows the same formula by having great build ups, and then an explicit sexual finale: there it is again... porn!
If you mean Single Again from Clever Name Games, that's the only one I've played from your list here. The one where the MC has a chronically whiny inner monologue, constantly questioning the sexual relationship he's building with his former step-daughters, trying to talk himself out of feeling that way about his adopted daughter while inevitably heading in that direction, and wondering if he should actually father a child for the lesbian couple they are all friends with. Oh, no, that game is not porn at all. If that's the one you're talking about, I can agree that it can be rage inducing, but I love it. Still, it has lots of very explicit sex scenes that would take a heaping dose of copium to call it anything but porn. I am not saying any of this is a bad thing, just call it what it is. When explicit sex scenes are shown, it is porn. A great story to that leads to that scene just makes it even better.