After running my Canon Macdennis Survey, it became very clear that the reason the fandom is so divided on the idea as to whether or not Macdennis is already canon is because people have pretty wildly different understandings of what canon means for a ship (and are even more-so when it comes to an enigma like Macdennis).
What seemed to be highly consistent with people who do believe Macdennis is already canon, however, is the idea that Macdennis, as a non-platonic relationship, is something that is intended by the show. That is to say, their relationship is written and acted in such a way that the audience is meant to interpret it as romantic and/or sexual in nature, beyond the surface level of pairing the two together for "the joke"
Since half the fandom doesn't view Macdennis as canon, and therefore their thoughts on this concept were somewhat limited in the responses I received, I'm curious to know from anyone and everyone in the fandom...
*Intentional does not mean that you think they will eventually "end up together", but that you believe the current, continuing writing for Mac and Dennis is intended by RCG to be viewed as something more than platonic and not just for one-off bits
(If you have nuance it can belong to one of these options with an explanation in the tags :D)