Tbh I like it that it's not possible. I think there's allready to many 'unlike' on the internet. If one dislikes something you could just tell them..I think that would be better. A button teaches the other person nothing, but it does make them less likely to post again. And everyone is bount to say something less enticing at some point. I think by respectfully telling someone they did something wrong in your opinion they can apologies, rectify or explain themselves. Just my thought on it.