That's not true. Everyone approved of MM when they married. We lined the streets. We watched them marry. The King gave her away when her own father was not present. We were delighted when she was pregnant. We were thrilled when Archie was born, though it was the first time things seemed a little off in that they seemed to want secrecy and not to allow the public to celebrate the birth, not announcing until they were already back home etc.
He was, because of his childhood trauma, incredibly sensitive to any perceived criticism of his wife who he couldn't have "hounded to death". He was and is terrified of that outcome. It leads him to over respond to any perceived unhappiness from her, or any perceived slight.
Unfortunately MM appears well aware of this and also takes on a role as victim who needs protection in the relationship (whilst actually being far more competent and cool headed).
Most of us only began to disapprove of H and M after they repeatedly accused the British public and their own family (not the press) of being racist, and lied about how badly treated they and their child were. Adding in all the humiliation of H's closest family in "Spare" and their netflix shows and we do have good reason to think them disloyal, paranoid, and accusatory.