Reading what someone has said can sometimes leave out context and other things. The person who the author thinks insulted her could have meant it as a joke. Contrasting the author with the stereotype. People try to get others to laugh and put them at ease. Sometimes they misfire.
If making a bad joke is racism then we are really defining racism down these days in order to victimize people. If the person truly is a bigot then their statement says more about themselves than their target. Why let it effect you so much?
Laughing is the natural human reaction to things that aren’t a threat to us, especially during moments of tension. We as a society need to learn to laugh more. Learn to laugh at stereotypes, at ourselves, etc… Then others will not have so much control over us that we need to make long articles/posts about us being victims of things that shouldn’t victimize anyone.