Why does Cowherd hate UM so much?

Please don't death blast me with neg points but I need an answer to this question. I did a search and nothing really came up. Colin just blasted UM/RR today, and he has done it plenty in the past, and it just pisses me off. I really like Colin but I have to change the station when he goes on his UM rants. He personally admitted that he has had some bad experiences with UM and its fans and called us rude, snooty, and hard to deal with personally and professionally. Was there a single event that I should know about that pissed Colin off and turned him against UM?