So if AT&T want to disconnect a customer for an arbitrary reason, fine: but they need to make it more clear initially, while considering their utility status.
If a gun store owner knew a guy was buying a gun to shoot up a school, wouldn't you want him to refuse to sell it? Wouldn't you want to hold the gun store responsible for knowingly enabling illegal activity?
(Note that I am using gun analogies in my comments because I feel the positions here are oddly tied to a specific issue, and hypocritical when applied to others. I'm aware these aren't really similar in severity by any means.)
What if AT&T's risk management software scores that its customer is "likely" to commit a petty crime by analyzing his traffic? Turn him off as well?
the ISP is like the roads that you take to get to the gun shop. Yes the gun shop should prevent you from buying a gun to kill someone.
The people who maintain the road to get you to the gun shop should not decide that you cannot use the road.