Incest is not cool for a variety of reasons, not just genetic.
For me it would be just genes.
Was it incest when the people who grew up in the kibbutz together ended up marrying each other? (and not blood-related, to be sure). Because they had affinity and the kibbutz community was a lot more family-like than many of today's modern families.
Today's modern families and villages are pretty messed up, and promoting the idea that "close" people (as we could call them) should become sexually involved creates additional problems.
We aren't talking about depictions of incest either. There is no relation between step-siblings/parents/etc. And in these videos, every single person is unrelated to every other person even in the depictions. The step-child has both a step-mom and step-dad... Where I come from, that would be an adoption? I would guess the next form of these videos will be adoption porn.
I assumed it was 'step' relative inorder to stop it being incest, and that it's basically a wink to the audience without changing the 'script'. Personally I don't think changing the title is morally relevant so it doesn't matter to me what precise relation the script and title uses.
Which takes us back to depiction, they're all actors so what ever the laws are, it doesn't matter. Or shouldn't.
The "step" thing is a get out clause. In the Netherlands, I've seen stuff advertised which doesn't even bother with that.
Adult incest is opposed mainly due to genetic risks in offspring and blood relation issues.
Otherwise, consenting adults should be free to do as they please.
If the "stepdad" and "stepdaughter" met as strangers, you wouldn’t care.
I don't think it's healthy for fathers and adult sons to be having sex with each other, for example. Or that any of this becomes okay when a daughter turns eighteen (or whatever it is in your jurisdiction) and her father wears a condom. That is psychologically and socially unhealthy. Nothing to do with inbreeding.
If a school teacher repeatedly had sex with pupils a day after they left school (and were legal adults), that would raise numerous ethical issues. Consent isn't some kind of carte blanche or moral justification.
If you have a moral objection to the content of the video, don't watch it, if you don't want to let people consume media that has objectionable themes, let's ban all violence as well, not just in porn, but movies, music, literature. No more Jason Statham, no more Daniel Craig, no more Dwayne 'the Rock' Johnson, no more Marky Mark, no more Eminem, no more Homer (sex and violence), no more The Bible (sex, incest, violence, rape, genocide, polygamy, slavery, child sacrifice).
"Step-cest" - a term I am sure has existed before, but I'm claiming it now, is make believe. And I'd bet 90+% of the watchers have it on mute.
this lack of biological relation is what facilitates the desire in the first place, and then comes the taboo
Incest isn't just "biological" as you put it, it is a matter of your relation to other people.