That's true. It would indeed give someone a lot of publicity. If, say, Cynthia McKinney did it, would it really cost her any support? I can't picture anyone who is still "on the fence" about her at this point who would decide that this is the final straw. (Mixed metaphor. Oh well.)
Maybe there is some party discipline at work here. Cynical me, I can't believe that EVERY house Democrat thinks that introducing articiles of impeachment would be "going too far." Something other than good judgment must be at work!