I'm not surprised that the dwarf in the original post jumped to the wrong conclusion, especially since he was drunk. As a minority, it's easy to become hypervigilant when it comes to perceived offenses. I grew up in the South, and as a gay biracial guy, I received quite a lot of negativity. It isn't always easy distinguishing between when someone is being a jerk for a specific "ism" vs. an all-around jerk. Perhaps it shouldn't matter, since at the end of the day, it's someone being a jerk, regardless of the reasons. However, it's easier for me not to take personally when, ya know, it's not actually about me, personally. That said, there was one instance that really made me cognizant of my own assumptions.
I was at a busy restaurant one afternoon. There was a woman in the corner who had yet to be served when I got there. I didn't really notice her at first, but after I had my order taken and appetizers served, I was surprised that there still wasn't any food at her table. I watched as waitstaff bustled about, and it was clear that each server thought that the woman was being taken care off by someone else. She was a blonde, thirty-something businesswoman, and not someone you'd think waitstaff would intentionally snub. Finally, she got a little irritated and said loudly, "excuse me, I'd like someone to take my order!" She received an immediate and emphatic apology and was quickly taken care of her. I thought about how, if I had been in that situation, I might have made some assumptions as to why I wasn't being served. It inspired me to always try to give people the benefit of the doubt.