Law of Categories
There will always be people that fit into certain categories and get along with people similar to them.
My dog is a monster :)
There is no way to get everyone into the same category and if there is we haven't discovered it yet. What we can do is understand that other people can fall into a different category. We can respect that and keep ourselves separate. The only time it should be deemed to be a problem is when one person's category affects another person's category in a negative way i.e. Person A has a dog that bullies other dogs at the dog park. Person B with a well behaved dog should not have to tolerate this. Person A should take responsibility to leave and seek training or permanently stay away from other dogs out of respect for everyone else.