Merle is poison. Any attempt to detract from that is a ruse. As a human being he has a sense of self preservation, and anything he does is to that purpose, but he is nevertheless poison, & the poison will always come to the surface
He would have eventually gotten himself screwed with the Governor regardless, & his brother telling him to go to hell is right around the corner, & has been a long time coming. He is a cancer where ever he goes, because his only way to raise himself up is by bringing others down
This is not a forgiving world in which they live (Unless you're Andrea I guess) Merle's way will get him killed eventually, because now more than ever, he must depend on others for his survival
But even that will not stop him from poisoning this situation at some point, because ultimately he will never see this version of his brother as anything but having been polluted with pussy liberalism.
His mistake is that he views what his brother has become as making him weaker, when in fact it makes him stronger, stronger than Merle has ever been or will ever be. If Merle ever realizes that, he'll be jealous, because he is a small pitiful coward hiding behind ruggedness & ruthlessness