I guess a little bit is all right, but doesn't it all start to sound the same after a while? The main points are; don't be racist, don't be sexist, don't be materialistic, yada, yada, yada.... Everyone is so over the top and self congratulatory. It seems to be more of a public speaking contest for sanctimonious showoffs, as opposed to poetry.
Om Mani Padme Hum
Okay, first of all, this is spoken word poetry, NOT slam, through many of the people on Def Jam are primarily slam poets. The following links are from some people who are, or got their start, as slam poets. You've find something different in what they say. Honestly, I'm not so sure I disagree with a lot of what you said, but I do want to educate you on what's actually out there.
Listen to these:
http://www.youtube.com/watch?v=ltun92DfnPY
http://www.youtube.com/watch?v=llFC762Kbg0
http://www.youtube.com/watch?v=px4ivPQol0o
http://www.youtube.com/watch?v=xsjcWGxKl9o