What you are asking here is to eliminate freedom of expression. By downvoting I voice my disagreement with your statement. Preferably there is a comment added, but that must not be necessary. Eliminating such a feature would give a distorted view of this community as a whole. One must live with the fact that not everybody has the same opinion.
>It's antisocial and pointless.
No, according to [0] antisocial is a behaviour that is contrary to the laws and customs of (a) society, in a way that causes annoyance and disapproval in others. In our society, or at least that is how I appreciate it, dissenting opinions are important and accepted. Yes, as mentioned above, a following argument would be nice, but isn't necessary. And also others must feel annoyed and be disapproving of it - not you. As to "pointless", see above.
[0]: http://www.oxforddictionaries.com/definition/english/antisoc...