From my experience, many people, the vast majority, are simply incompetent human beings. 

They cannot help anyone else but themselves they think and are dead set on practicing just that: survival of the fittest.

Of course, these people are really really selfish and often controling more than tolerant.

But truly, at some point, you HAVE to listen to your loved ones point of view. Their experience might very well enlighten you if you are not too fucked up with paranoia or anger.