they play with human psychology, and when they post such things they knew it will catch the attention and people will be bound to respond as a result of anger and hurt. they do it for the sake of fun and try to criticize others, and in an attempt to hide their own weaknesses they exhibit an uneducated behavior. We can not excel in controlling our emotional drive for the reason that we are humans, in one way or another we get emotional at some point of time. that's why we can not stop ourselves to respond when someone try to become judgmental on such platform which is used by multiple nationals.