The world is full of people. Some good and some bad. It is all in one's perspective how we view them. Kids need to learn to deal with all types. This Mom is one of those types we'd like to have our kids not have to deal with but they are out there. At some point your young lady will have a supervisor, or other authority figure, in her life that will be as negative as this one.

Our job as parents is to help our kids learn to cope with all of the adversity's life deals them. It sounds to me like you did that and your daughter came out the better for the experience. I don't see it as bad - I see it as an opportunity to help your child continue to grow and excell as a human being. To learn forgiveness and new ways to cope with life's little lessons is a valuable thing. Sounds weird but you ought to thank the Mom for giving you this opportunity to further the closeness between you and your daughter. Doesn't mean you have to like or associate with the mom but it certainly would reframe what the mom said and the impact it had on you and yours.

Steve