It's why I personally ignore TOR as a canonical entry.
It is an official entry, yes, but it felt like an insult to Revan (to have him submit to Vitiate so easily) and removes the interesting implications of Kreia's assumptions on Revan (that he never truly fell but was trying to prepare the Galaxy from the True Sith though I am aware Kreia is a wee bit biased here). So I personally ignore TOR from canon (then again with EU being mostly non-canon, that's not hard).
Though I'd argue Malak would submit to Vitiate. His lack of any wisdom (bombing an occupied city of his forces, spam using the Star Forge - that has horrible consequences for said spammer, ruining Revan's plan to prep the Galaxy from the True Sith etc.) would make it easier for someone like him to submit.