I completely agree. I adore Mary, but she does have a tendency to be self-righteous and judgmental. And she is not good at admitting when she's wrong and owning her mistakes. (Oh, LORD her hypocrisy sometimes.
)
Not that it excuses Darnley's behavior at all, but I do think it is a direct reaction to how Mary is treating him. I truly believe he is capable of changing and being a better man. She only needs to give him a little encouragement and hope.