When people say dumb things on your page, it's a good thing.

 "Anyone who has anything bad to say about Rosa Parks is kind of a dick."

I just had a friend post that status. I only know vaguely about Rosa Parks but I do know today is some special day. I think it is her 100th birthday. Either way, I don't know enough to know if she did something that others can run her character down for, but I highly doubt it.
I get where my friend is coming from. It isn't really your place to run someone down on someone else's page, unless they glorify someone who is clearly a deviant, like say Michael Vick or Jeffrey Dahmer. But otherwise, if you don't like it, just delete them.
However, I think it is a good thing when these idiots do it anyway on your page. Stay with me here.
We make so many friends on facebook that even if we wanted to vet them all out we never could. We simply cannot know that much about them that we could exclude everyone who ends up offending us or our friends for any number of inappropriate reasons.
I don't have the time nor the will or desire to do that. I try to investigate as much as I can. I, like many others, mostly use my first impressions and instincts and do a bit of homework. Most times my determining factor if I am unsure is the mutual friend factor. That works, most of the time. But it is easy for a number of people to miss a sexual deviant, dumbass or just plain no good moronic idiot who has no class. 
You would never find out that you have one of those sitting on your friend list, unless they show themselves by making a comment such as my friend was referring to above.
I had this happen a few months ago, when a guy I was warned about but who seemed okay to me finally showed himself by making a very racist and extremist comment about Jews and Americans. It wasn't a minute later that he blocked me when I called him on that. If he hadn't blocked me, I would have blocked him. And if he hadn't made that comment he would have lingered and likely made more friends off my list. So, in effect, he did me and my friends a favor. 
It was a good thing, even though it seemed like a bad thing. I would rather know the devil I have lurking than put my head in the sand and just never want to know. If that means I have to read or listen to some Ann Coulter or Rush Limbaugh wannabe once or twice first, I am okay with that.