Like a bunch of other catch phrases in current America*, "some of my best friends are..." is supposed to bring argument and discussion to a halt. The phrase triumphantly points out that the person noted is covering up his bigotry and prejudice about an approved minority group by pointing to the exceptional member of that group whom he likes. It is a way of counting coup in PC: You are clearly a hypocrite. End of story.
Some particularly dense young man was arguing on Facebook this morning about the Ground Zero mosque, saying that he knows some Western Muslims who are very nice and do not want to blow anybody up. Ergo, stopping the mosque is un-American, etc. Why punish these nice Mohammedans because of a few fanatics? After all, remember the Spanish Inquisition, etc.**
People as individuals and people in groups are not the same people.
Making that distinction is something that many humans have always done. Separating a liked individual from a disliked group: nothing is more natural and there is nothing inherently wrong with it. (Hell, if you like a group of people but dislike an individual in that group, is that hypocritical?) Because: people as individuals and people in groups are not the same people. Ask a Tutsi about a Hutu. Need I go on?
Just because you like the person as an individual does not at all mean that you must transfer that affection to their group(s). One of my best friends is a Unitarian. Wonderful human being. Despite the fact that her religious group is nuts. There is hardly anything they stand for that I can stand. My ex is a black man who remains my good friend; but ask him about his general attitude toward white people some time. Not pretty. See? It goes both ways. So I don't feel at all bad (or..oooooooh....."racist") for taking a dim view of a great deal of American black culture and behavior.
Hell, what about all the mixed marriages in history? When people marry, no one expects the spouse to automatically love their new partner's family. On the contrary, it's a staple of humor that while the couple loves each other, they can't stand each other's family. As with family, so with a lot of other groups. Human love is not restricted by group boundaries, but that does not mean that the boundaries are illusions. Good fences make good neighbors.
I just read this morning that Ann Coulter and Bill Maher are friends.
That PC nostrum, which requires you to love all members of a group if you love one member of the group is just as stupid as the literal stereotyping which holds that all members of a group must be a certain way, without exception. Both of these extremes simply do not pay attention to reality.
*"racial profiling", "separate but equal", "second class citizen", etc.
**And don't get me started on "moral equivalence". That's ready for another posting by itself.