Actually it doesn't!
The word "proship" does NOT stand for problematic ship! The "pro" is actually Latin, and it's a prefix that means "for". Proshipping literally means, "for shipping".
Proshippers (like ourselves) believe that all people deserve respect, no matter their ships. Proshippers do not have to indulge in problematic content to be proshippers! We're one of those―we don't actually have any problematic or dark ships. (Our OTP is kazuhei lol)
The term for problematic, dark ships is "comship". Does comship count as child you-know-what? Nope! Actually, comshipping is protected under the 1st amendment (case went all the way to the supreme court)! So it fictional child you-know-what, as long as the minors are fictional.
Plus, comshipping is actually a very healthy coping mechanism, because no real person gets harmed. It's not self-destructive like sh or substances.
Here's some resources for you to look into why comshipping is not all that bad as you think! There's a lot to read. https://comship.carrd.co/#c10
Lastly, at the end of the day, ships are stories. People can enjoy books and tv shows with problematic characters and tropes because they're written/produced well, so why can't people enjoy ships with that? Why are people allowed to simp for problematic characters but not enjoy problematic ships?
Plus, keep in mind that neither proshippers nor comshippers ever endorse problematic things irl. We hate real abusers/pedos/groomers/rapists too. If someone is actually endorses that stuff irl, then they are disgusting.