Before i get into this let me preface this with the "not all Leafs fans" statement and it's true, there is a vocal minority that this post is about.
First, it's not an obsession, it's frustration at the Leafs fans delusions that Matthews is even remotely close to McDavid.
Mathews has broken 80 points exactly twice in his career, has one 50 (yes I know he got to 60) goal 100 point season. and is not even in the same ball park as McDavid. I don't need to list all the things McDavid has done to prove he's in a class well above Matthews.
And Draisaitl has 3 100 point seasons, 2 (very possibly 3) 50 goal seasons, the only active player not named Ovechkin to have multiple 50 goal/50 assist seasons in the NHL. and Matthews "incredible 60 goal season" beat Draisaitl by a whopping 5 goals.
Yet Leafs fans constantly yell to anyone who will listen that their superstar is better than Leon, and on the same tier as McDavid, then say "why are you obsessed with Matthews?" when Oilers fans throw facts at them that Matthews is not as good as either of them.
Matthews is the 2nd best player on his own team let alone on a tier with McDavid.
Oh, and "pace" argument is junk. If a player didn't hit it, regardless of his "pace" it didn't happen.
If you want to use the pace argument, this would be McDavid's 7th consecutive 100 point season, as he had 97 points in 63 games when the league shut down for covid, which would put him 2nd all time to Gretzky's 13 consecutive 100 point seasons.
Stop shoehorning Matthews somewhere he doesn't belong, just to make you feel better about your own insecurities about your "superstars". Everyone knows a portion of Leafs fans are still salty, and will always be that they lost the draft lottery and were somehow "robbed" of McDavid. And because of this you prop Matthews up to tell yourself, "it's not a big deal we didn't get McDavid, we got Matthews, and he's just as good!" That's where the true obsession/delusion lies.