Rhysand drugged Feyre and made her dance and be humiliated UtM, but you can understand, forgive, and ship feysand.
Nesta insulted Cassian in a way she knew would hurt and literally kicked him in the balls, but you can understand, forgive and still ship nessian.
Elain and Lucien have spoken like two words to each other, but you ship elucien.
But somehow… Mor and Az, who have shown kindness and caring and consideration for each other, against whom the only really argument is “what have they been doing for 500 years?”… that’s too much. That’s where you draw the line.
***I want to point out that I do ship all of these, to more or less of an extent. I, too, understand and forgive, for the most part. But… sometimes people’s attitudes towards moriel baffle the fuck out of me.