Merthur is the greastest ship of all time. It may not be canon on the show, but it's canon in our hearts. So, that makes your argument invalid. Two Sides of the Same Coin
Interviewer: Which do you think is stronger: Arthur’s romance with Gwen or his Bromance with Merlin?
Bradley: Bromance with Merlin. It’s…It’s there for everyone to see. He’s been round for dinner at Gwen’s, he spends all his time with Merlin. No contest.
All I want to say is “Thank You”, Bradley, for saying what all Merthur shippers needed to hear.