This happens for many reasons. Someone is closed off, someone is too old to change the way they already think, and there are those that think they know everything and will not change their mind.
Life, as it has been said, is like this everywhere you turn. The only way to even remotely fix this is to change yourself, help others and maybe then it will no be this way.
There are people bashing. I'm sick of seeing it, personally. I go by "If you have nothing nice to say don't say anything at all". Though, this is not the case for the majority of people.
Sometimes it seems growing up and being mature and tolerant of others is out of reach.