When the action is as important as attempted worldwide genocide, and has not been invalidated or contradicted, then yes, I think we don't really have much choice in the matter. It happened, deal with it.
And yet that didn't stop Xavier from having Mystique be his agent, or the X-Men from giving her a probationary place on their team.
And Thanos has done far worse, and that didn't stop him from redeeming himself.