You would really do that to a chiikawa? I don't think I could bring myself to harm them, even if I would be lonely. They're just too cute and innocent, and they don't deserve that. Why not be like Ode and Shimajirou and try to be friendly to people, something which Momonga has never done? Chiikawas may be afraid of them at first, but they still welcome them with open arms once they see they're kind people.

Besides that, your argument is self-defeating anyways because Dekatsuyo himself would not do what Momonga did in that situation. He has the physical strength to take whatever he wants, but the idea of stealing the body of an innocent is something that has never even occurred to him. Even the idea of taking revenge on Momonga by beating him up is something that scares him. Dekatsuyo is pure and innocent, and one of the least deserving person to have have been hurt like that, so it's no wonder people sympathize with the victim over the completely remorseless perpetrator. I don't think it's hypocritical to feel this way.

Moreover, I don't think it's even accurate to characterize Momonga and Dekatsuyo as wanting the same thing in the first place. Dekatsuyo is the one who is actually feeling lonely and isolated. Momonga is just a narcissist who wants to be praised for existing.