Well... I suppose that things like that are pretty common, actually

Your feet may appear big, or are bigger than the person who said that to you.
Punching people is not intentionally, but does happen a lot, especially when the dancefloor is very crowded and people dance very "dangerous" patterns.
When you dance competitively, height is one of the most important things to make a "perfect picture" on the floor. Of course, there are exceptions (Matthew and Nicole Cutler, for example), but overall height does play a big (pun intended ) role. However, she (the lady you were talking about) could also find that his kind of height is not very comfortable for her.

I can name a zillion of silly stuff, but I guess it's all part of dancing