I think Gray farms covered it quite well, but I'll second it. While he is a very handsome cockerel, he isn't really a good fit for the AOV (all other varieties) Class. It's possible that his comb earned him the DQ but it's equally possible that it was his coloration.
Ameraucanas are show-able in eight different varieties: Black, Blue, Blue Wheaton, Brown Red, Buff, Silver, Wheaton, and White. Varieties not accepted into the APA Standard of Perfection like Lavender would be show-able in the AOV Class. Because his color doesn't follow any true pattern, the judge didn't examine him any closer.
Just like the Silver-laced Orpingtons I raise are not an APA accepted variety, they would need to be shown in the AOV class versus competing against their approved variety counterparts' class. However, because they are English rather than American-type it's possible they would be DQ-ed on type issues alone.