Our kiddo is only 4, but she is VERY vocal about who she does and does not want in her space. I would say invite people over for a platonic only, short visit the first time to make sure kids feel safe enough. If kids have no objections, then person can come back for sexy time. If kid does not feel safe or have other legitimate objections, person only comes over when kid is not home.
That's how we do it. If plans are made with disliked person when kid has other plans, kid gets to decide if she'd rather be around person or not but does not get to affect other people's plans -like this weekend kid and I had plans with a friend. Disliked person was coming to see Hubby. Kid wanted to change plans to stay home. We said fine, but so and so WILL be here because dad also made plans. Kid chose to not be around disliked person and stick to original plans.
I don't know that I'd want to give a 4 year old control over who comes to my house. I've always made it clear to Kiddo (he's 10) that I'm a person and not just a mom, and yup, that means I get to have friends around if I want them. I guess I'd wonder why this person is so disliked- did they do something to my child that needs addressing? Because kids tend to be pretty easygoing. If Kiddo didn't want to be around my friends, he's welcome to go to his room or be in a different space. Kiddo's space is his room; he doesn't dictate the whole house!
I just can't imagine having people that I'm willing to fuck but not be willing/able to socialize with them in my home without it being sexy time. That totally breaks my brain. What, do they wear giant flashing stickers that says "we're only here for casual sex"? I don't see how there is a problem if everyone behaves respectfully. I agree with ref that this thread seems really odd/blown out of proportion. And the idea of calling them "sexy visitors" even weirder. They're also human beings, I assume