I think he's just very good at manipulating Dutch because both men are very similar at their core: murderous thrillseeking criminals to whom "fighting is in their nature" as Dutch put it at the end of RDR1. Micah realises this and doesn't fall for the philosophical/political yapping, he sees right through Dutch but he plays along and strokes his ego to get closer to him to eventually capitalise on it by selling him out to pinkertons.
Hosea and later Arthur both realised this but ultimately couldn't salvage the situation. The rest of the gang were too mistified by Dutch's bullshit to see what was really happening until the very end.