Prove them wrong.
When my sister was in high school she was 5'2" tall. She was laughed at so hard by other basketball teams, until she completely blew them away with her moves and her shooting ability. She turned out to be one of the most recognizable basketball players in our league because she wasn't what they thought she could be...
So, screw them...if they look down upon you for having a colorful horse, go out there and show off the training. It doesn't matter either way, you will be remember when everyone else is forgotten because of the horse.
Yes, the Moondance Alexander movie is exactly what I thought of too!
^^^ 100% agree. Let this motivate you, not dishearten you. When I was a teenager and showing, I had this one man (who today is very well respected in the training world, so I cannot mention names) who was judging in halter classes. At the time I was showing a fantastic appaloosa gelding who ALWAYS placed very, very well under halter, with the exception of any time I ever showed under this particular judge - we never placed. On one occasion when my horse had performed beautifully and I walked out of the class empty handed, I questioned the judge directly about it, and was told "I will never
place your horse in a class. I don't like appaloosas anyways, and I think your horse is ugly." I'm sure it took a lot of guts on that grown man's part to make a 13 year old little girl cry like that, and I was furious for a while. I probably could have told someone what he said to me and something would have been done about it (and prevented him from having his big-name lucrative career, ahhhh hindsight!) but the point is, I let it motivate me instead of get to me. I worked even harder, longer, than anyone else, and doubled the number of ribbons I brought home with my "ugly" appy. The thing is, opinions are like, well, you know. Not everyone will like what you've got - and some people may be biased against your horse due to breed or color - but let that give you a reason to prove them wrong!