Which is somewhat consistent with his 'other people's suffering is insignificant next to mine' remark. It's not a denial of other people's suffering, and that suggests he'd do what he can to lessen it, but only so long as it doesn't interfere with his plans. Haruto and Mayu are willing, so he lessens their suffering by permitting them free will, because it comes at no (immediate) cost to him. Yuzuru and - and Todoroki I can't remember his name are unwilling, so he just brainwashes them. Painfully, if Yuzuru is any indicator - look at that inflammation under his eyes, man.