Nowhere in your link didn't it mention sex toys cause a rectal prolapse. So maybe link something appropriate.
Also, people generally don't start straight up shoving huge sex toys into their orifices. It's built up and if it's a problem then they stop.
Personally, I don't want anything that big near me. But if others want to, it their bodies, they're free to do whatever they want.
The air we breathe causes our cells to degrade which results in aging and death.
Smoking is bad for you.
Junk food.
Alcohol.
Drugs.
Skydiving could kill you.
But it's not our place to police what people do with their own bodies. If they want to snort coke off a hookers ass, then that's their choice.
If someone wants a giant dick in their ass or vag, that's also their choice. If they cause issues for their own bodies, they're the ones making the choice knowing any risks. It does affect you, so why are you all up in people's business that doesn't affect you?
Stop trying to police people's bodies and what they do with them.