Well, it's just a case of T1 players quitting matches before they start, in order to drop their MMR score. This is why you're up against them.
For example, I'm T1 rank 4 (purple) and with a 40% MMR score, I mostly have Raider team mates who are rank 6 and unranked a large portion of my games. As an Antagonist, I'm up against 2-3 T1, rank 1 players in a team and it's incredibly hard. That stated, if you can win, their skill bonus will really boost your score. But probability is you're going to lose. LOL