"The logical argument against having sex in the street is the same as against shitting there: because it's a public health issue and no one wants to step in it."
As I said before, that's why you make it a law that you have to clean up afterwards, just as people who walk their dogs do.
"Also constant sexual stimulation diminishes the pleasure to the point where you need to take a break for a while."
That may be true for you, but not for me. Of course, after sexual activity, your body needs a rest (how much differs both between genders and among individual persons) but I have never found the same to be true about my mind.
Even when I'm ill and stuck in bed, and my body wants absolutely nothing to do with sex, I still derive much enjoyment from thinking about it and mentally envisioning it.
"I mean fuck, porn is great and all but I don't want it in my face constantly either."
I love music, but it annoys me when I'm walking down the street and a car, residence, or business is blasting it into the open air. I'm not talking about "my eardrums are bleeding, I'm going to call the cops." It is neither illegal nor causes me physical harm, it simply annoys me. But I recognize that that's MY issue. And I don't get to tell other people to stop doing something just because it bothers me. Unfortunately. ;)