I think that Diego sees a gold mine way to make money and help people and doesn't see the problem about why the existence of the aliens should be kept a secret, they're just things to him, things to be exploited for the betterment of humanity. He sees the HUGE opportunity that Liz's work could do but doesn't understand why she won't take that next step, why she's holding herself back, and I think that he's allied himself with people that won't care how they get the material for Liz's serum or whatever they'll just take what they want...
I don't view Max as boring, he's just not as wild and crazy and carefree as Michael and Isobel, who really have little to nothing tying them down to anything or anyone in comparison...