That rude motherfuck oh his mind is mosnterizing, well that explains a lot.
If he had offered money to Saitama he would have listened, but someone with the one tracked mind of a monster wouldn't have been able to see others perspectives, i bet he still hasn't figured out that Saitama is only hanging with him for the free food.
Making Sweet Mask an actual monster that stills has part of his human mind makes for an excellent scenario, because despite his intentions being for the better of mankind you can easily see how his obsession can turn him into a villain, something that we never got with Garou since he was just playing at being a monster while being on denial of his heroic actions.
In here however Sweet Mask has to fight his own mind and try to implant a counter measure so that his eventual downfall into complete monsterhood doesn't brings a calamity, but of course he is failing because as a monster he can't understand what motivates those different from himself, so he insist on talking from his own desires, for him everything is decided by appearances, masks and public opinion, and he can't no longer see past that, but the fact that he kind of knows what is happening to him makes this really interesting.
@Serenata Garou was never a monster, his "monster form" was a suit made with the blood and parts of other monsters that stuck to his body, he was a human playing pretend monster, Sweer Mask is a monster that is on the process of losing what is left of his humanity.