I respect the skill that Brock used to beat Mir, he was better, he won. Mir is a BJJ black belt, and even he knew he made some mistakes. Lesnar is a strong and skilled wrestler...and he can hit. There have been many champions in the UFC with those credentials.
What I do not respect is continuing to go after him (Mir) verbally after the fight, I don't respect the way he conducted himself in the interview with Joe. If this does not bother you, that's fine with me, but is shows incredibly poor sportsmanship, and a complete lack of respect for his opponent, the organization and the fans (or at least some of them).