Immediately, I would say. Regardless of why it's being done or who is being targeted, isolating and ridiculing an individual is a form of bullying.<p>Whether they realize it or not, those who are the most vocal against bullying or intolerance often end up being among those people directly engaging in such things.<p>One inherently can't speak out against a particular bully without partaking in bullying himself or herself. Likewise, one can't truly promote tolerance if he or she does not tolerate those who engage in intolerance.