Why so much hatred out there?

This is an observation I have made over the years related to the society in Sri Lanka. Hatred!. People have started to hate almost anything. One example was the hatred demonstrated on facebook with the exit of Pakistan and especially India from the world cup. Its perfectly acceptable to have grudges against some, which is generally the case with anybody's neighbor. But, is it nice to see you write hateful comments about it on your wall? (May it be physical or virtual). What is demonstrated by these outbursts? I posted on my fb wall to find out why this is happening and got many interesting answers. Here are some reasons why they hate India,

1. They voted against us in the UN
2. Big headed people in the team
3. Think they are better than us
4. Implanted the civil war in SL

While these may or may not be true, that does not give anyone of us a moral guide to be rude to be at them. Doesn't that make us even lower than the accused person or nation? Is this another side effect of having a war for 30 years and the need to see and hear bad things? I am totally stumped by this question and think its about time we start discussing these symptoms before the sickness gets worse.