My story, my rules, you're welcome to help but it's not your story to mess around with!
I've been upholding that principle for a long time here. Had several experiences where people casted the wrong actors on my stories, so i had no choice but to put some rules on my own stories.
For examples:
1. Let's say, if i want my story to only have Japanese actors, then non-Japanese celebs are NOT allowed.
2. Or this, if i don't want super popular celebs like The Rock, Tom Cruise, Brad Pitt, Chris Pratt, John Cena, Tom Holland, Zendaya, Blake Lively, Ryan Reynolds, Gosling, or Keanu, Leo etc. in my stories, then that means they're NOT allowed to be in my stories, don't try to force them into my castings.
3. Last is me not allowing people casting several problematic celebs/celebs with bad reputation or basically people who aren't even actors (+doesn't have any good acting skills even if they did a few movies or so) into my stories.
It is one of the reasons why i put warnings and reminders on the descriptions of each character roles on my castings.
Imo, YOU made the story, so it's technically YOURS and you can do anything you want with it.
Although i don't outright vote 'NO' unless i think the actor in question is the one that i think not a good fit to play the particular character role. And I immediately block people when they cast troll suggestions or any kind of awful sh*t.