If he was shouting his ignorance as a way to make the losing bidders feel even worse, then he was rude. If just generally clueless, then no. Since I don't know which he was, I will give him the benefit of a doubt, and say not rude.
But he has violated the number one rule of collectors: collect for love and not for an investment. If the market for the collectible falls apart, but you bought it because you loved it, you can never lose.