He's seen her being a manipulative thot multiple times. Even cursing at someone trading their lives for her safety. I am baffled that this kind of MC is popular in JP. At any cost, at least the author somewhat punishes the MC for being incredibly incredibly incredibly stupid. Too many authors let the MC go scratch free.
The author redeemed (partially) a bit of himself due to the stupidity that he made several chapters ago when he let MC got away with his stupidity.