Are blackboard, whiteboard, and flip-chart offensive terms?

Some people are easily offended. Personally, this seems like a really stupid thing to get worked up over, but what can you do. The business world is diverse and I think a lot of the jokes about businesspeople being overly "pc" come up because culturally sensitive euphemisms tend to become ridiculous. I don't know about the flip-chart thing (how is that offensive anyway?) but if you want to drink the kool-aid, you can refer to the other items as a chalkboard or a dry-erase board.