It's easy to discount something you have no experience with. After all, you have no experience with it. You haven't touched it. You haven't observed it. You don't know its quirks, its disposition, how it reacts when poked with a stick.
Some people like to speculate, despite having no knowledge of the thing they are speculating about.
We like to do this. We like to think that we are informed authorities about things that we really know nothing about. We like to do this with people, probably more than anything else.
It's easy to lump everyone together and buy into a perpetuated stereotype. It's easy to say that all people with quality A and quality B are all alike. If you really stop to think about it, it's a little ridiculous, but it's easy to say that.
When you know someone who is gay, suddenly it becomes a little easier to be sympathetic towards gay people. When you know someone who gets sick, suddenly it becomes a little easier to be compassionate towards people who are sick. When you know someone who has an emotional issue, suddenly it becomes a little easier to be understanding towards people who struggle with their emotions.
When you're willing to reach out and know someone, suddenly it becomes a little easier to have love and compassion for your fellow man.