Responses
You make an excellent point. When I find things like this in manga, or any medium, I take it as a lesson I can learn from someone else's pain (even if the someone else is a fictional character). "Take care with your thoughts because they become words. Take care with your words because they become actions. Take care with your actions because they are your character." It all starts with changing how we think.
While the uke isn't the nicest person, he doesn't exactly deserve the hate either. He did warm up a little but that's just how he is so why're the comments full of hate? I personally have mixed feels for him. The only thing that I'd like him to change is his choice of words. There are so many situations (actually once every chapter) where he'd say something hurtful like 'disgusting' but then he actually has a follow up which the seme finds it cute. Either he could choose another way to phrase it to at least not hurt others so much since he's so frank or he could just say the follow up right away before the seme leaves.