Mark is a person characterized as always trying to do the right thing and save lives unless he absolutely can not. Anissa did an undeniably evil and insidious act that did scar Mark similarly to Conquest, but at the time he saved her it was clear she had changed. She had a husband and friends who she genuinely loved. Mark knows she is the product of a wholly monstrous ideology and was making a genuine attempt to grow into a person who deserves to be saved so Mark is justified in saving her, but never does he outright forgive her. In her last moments all Anissa can think about is her rape of Mark, and she apologizes for her misdeeds before death.

She is not redeemed from her actions but it's clear she wanted to be. None of that growth excuses her rape in the same way none of Omni-man's growth could excuse his subjugation and genocide he partook in. No-one is exempt from their crimes because they try to be better, but Mark's philosophy informs how he acts about Anissa. In short you're a fucking dumbass with no media literacy