1. Donald Trump has already proven he has the mind of someone who commits sexual crimes and has admitted he can't even stop himself from kissing, grabbing someone he's attracted to.
“You know I’m automatically attracted to beautiful — I just start kissing them. It’s like a magnet. Just kiss. I don’t even wait.”
Furthermore he has indicated he uses authority over someone to compel them to comply with sexual advances:
“And when you’re a star, they let you do it,” Trump says. “You can do anything.”
“Whatever you want,” says another voice, apparently Bush’s.
“Grab them by the p---y,” Trump says. “You can do anything.”
This is, of course, in addition to the numerous reported cases of Trump forcing himself upon women in his employ or participants on his show and in his pageants.
2. Furthermore Trump has an absolutely disgusting record of making reprehensible comments about his daughter's sexual appearance and taking far too excessively sexual photographs with his daughter.http://www.independent.co.uk/news/world/americas/us-elections/donald-trump-ivanka-trump-creepiest-most-unsettling-comments-a-roundup-a7353876.html
3. It is a natural assumption that, given he finds his daughter so beautiful that "maybe he'd be dating her", his inability to keep himself from being too forward with someone even when he shouldn't, and his record of taking advantage of people he holds authority over (of which "child" fits the mold even better than "employee"), that Trump may have sexually assaulted his daughter and I don't understand how this is such a horrible thing to ask about when the corroboration of publicly available evidence points to the very strong possibility that Donald Trump did do this.
It's a legitimate thing to ask about because it's very possible something related to this might even come out as an October Surprise soon!
4. Why go out of the way to limit discussion about this man's disgusting behavior and its possible implications when everyone just seems to be letting literal erotic fanfiction
be on the front page of the 2016 board with nobody even lifting a finger to stop it? Isn't that frivolity a little bit worse than genuine concern for the welfare of people who Trump might have abused?