Errr...I disagree....sometimes saying nothing is collusion...especially when it impacts on you and makes you uncomfortable.
Yes thats what I thought too, but have since spoken to a co-worker who told me not to say anything, she has been working for the company for 30 years and says she constantly hears racist comments from staff and it really upsets her.
However her dad used to be a union rep for another industry and had to deal with lots of incidents of this nature and his advice to her was to say nothing because it wont help in anyway, nothing gets done about it and it just creates animosity.
I found that quite shocking to be honest but can see his point.