I didn't interpret his comments as if he "literally" hates Witten. I believe he's speaking from a competitive standpoint and from a jealousy standpoint. Obviously, Witten was the guy they wanted MB to be like, but he didn't want to be like him. He wanted to be MB. And being constantly reminded that Witten is who he should aspire to be and not getting as much playing time because Witten was on the team developed within MB a "hatred" for Witten.
I, personally, think this is a big ado about nothing.