People eat animals they're used to eating. There are millions of people in this world eating dogs because it's normal in their culture, and millions on the other side of the world who think that's atrocious because it's not what they're used to. Seeing a chicken perform complex tasks isn't going to stop someone from eating them if they've been conditioned to believe that's normal and they're used to it and everyone around them does it. People won't eat a dumber dog or spare a smarter pig. It's not about intelligence, it's about perceived superiority of specific groups.

Abusive parents aren't more likely to abuse their dumb children, nor are they less likely to abuse a child that is smart. In fact, many abusers hate intelligence and will specifically target smarter victims. Otherwise, all the nerds would have the best time in high school, but that's generally not the case.

In the end, someone who is willing to abuse will find a reason. Don't put the blame on the victim. That doesn't help anybody.