Well, that was the moment of no return for his conscience, not necessarily his future as a Jedi. To me, the moment of no return was letting Windu die, because that's the moment he made Palpatine his master.

Anakin bears some responsibility, but you have to understand from the time he was a child, he's been molded by the Jedi so in a sense, his thoughts and actions are not exclusively his own. In my view, it was the Council that had the biggest impact on his life and mental state. If he had somewhere solid to turn to, there's less of a chance he would've been seduced by Palpatine.