"Well, a lot of people think sex bots (all of them) should be banned because it somehow dehumanizes people or something. I honestly don't fully understand the argument which is why I'm asking questions because the argument put forward does not seem logically consistent or based on any scientific studies."

I can help with this part.

Modern day feminists have a bit of a subconscious fear of losing the sexual marketplace stranglehold. Right now women tend to hold all the cards. In birth control options, sexual access, etc. "Sex Bots" even just the "normal" version of that is a threat to their sexual monopoly. Guys might stop playing the game altogether because it's less hassle to just buy a VR program or robot. And since feminists aren't the most attractive of the bunch as it is...

Now, they don't admit this to themselves, so they go on crazy tirades about objectification as though it's going to be much worse and more widespread than:
All advertising
Video Game characters
Mannequins
Models
Risque jokes, stories, and whatever else
The vast porn repository of the internet
Etc.

It doesn't make sense logically. Let's be real, creepy though it might seem a freaking robot is going to be a luxury good. This isn't going to cause an epidemic of objectification. Even IF we thought having one caused that (no scientific study backing this at all) it's going to be prohibitively expensive.

But that's part of the problem. Expensive means the best providers, the guys that are some of the best targets, won't need them any more. And an aging feminist has basically no options as it is.

Just my take. This is all sexual chess. Women see the potential to lose a powerful point of leverage and are resistant.