At my old job, I managed to escape the "mandatory" diversity training by just not signing up for any of the sessions. My co-workers reported to me that the training was essentially a course for Anglos, particularly males, teaching them how to walk around on their tippee-toes when dealing with various non-Anglo groups (i.e. "people of color," "people of ethnicity," and "people of gender"). .
The aspect that attendees found truly offensive that the training was performed from a standpoint of "you're all white male oppressors and harassers," as if people of color, ethnicity, and gender were incapable of harassment and racism. Yeah, my politics and overall point of view lean to the left, but I've just about had my fill of guilt for being a perceived member of the lucky sperm club.
A quite by Mark Helprin says it better than I could -- "The reduction of 250 million individuals to a handful of racial and ethnic classifications is not the recognition of differences, but their brutal suppression."