Why is yaoi much less explicit in hentai than usual straight stuff?

I understand that Sensitive Pornograph is an outlier along with others, but in terms of hentai in yaoi manga and anime, it’s not as explicit as hentai in straight manga and anime. You can go and look at a great number of straight manga series or animes with hentai in them, and they get very graphic, with great amounts of semen and such and showing all the good bits like penetration and internal stuff.

But when it comes to yaoi, a bunch of it isn’t as explicit or graphic, especially in anime. Don’t get me wrong, I’ve seen a great many of manga with hentai in it that’s explicit, but majority of the time, it’s with two guys that look extremely pretty and beautiful having sex that isn’t particularly graphic or hardcore, like Haru o Daiteita or Papa Datte Shitai (nothing wrong with that if you’re into it), while straight manga and anime is more graphic and hardcore, with things like Mezzo Forte or Kuroinu. If you compare the four, two of them are more hardcore than the other two. You have stuff like Goblin Cave by Sana, but that seems rare in comparison to all the other stuff out there.

Why is it that hentai in yaoi manga and anime seems to be more subdued in terms of explicit and hardcore sex vs hentai in straight manga and anime? Thanks in advance!