So I've done pretty much every LSAT test since 1993 when I studied for last year's December LSAT. One thing I noticed was that the attitude of the author when writing about ANY AND ALL minorities was always positive. It was always a glowing review of the person' work, or their contribution to the world or whatever. It was never a critique. On exam day I had a passage about an African American painter and sure enough, positive, I think it's safe to say that when dealing with a passage about a minority it will be a positive attitude.
I'm not the only person who thinks so. I read this recently in an LSAT prep book. Apparently the lsat doesn't want to be seen as racist in any way so all passages are carefully selected to be positive.
Thought this might help.