should not justify violating the Creative Commons License
Absolutely. Even a guilty verdict shouldn't justify violating the Creative Commons License. It should either be completely taken down/hidden, or left in-tact.
That's not at all what I'm saying though though, I'm saying that it's reasonable for the site to take action to hide the account. He's a public figure with an apparent confession, which is going to attract a lot of attention to that account that otherwise wouldn't be there. They shouldn't have done it this way since it violates the Creative Commons License, but I am saying that action to hide/disable the account is warranted.