They try their hardest not to be the "homers" which was and continues to be a chronic complaint around the rest of Canada that both TSN and SN were nothing but "Leaf casts!" However those same people weren't able to acknowledge that the viewer and listenership is concentrated in the Golden Horseshoe which happens to be largely Leaf-centric. The advertising dollars are always going to dictate what comes over the airwaves, and if a 1 minute block only has 2000 listeners and 800 viewers when "talkin Oilers" is on and the same 1 minute block has a 12,000/6,000 split when talkin Leafs is happening, guess where most of the money goes?
It's not rocket science, but the truth is that networks are afraid of labels and so tone down the positive Leafiness in their broadcasts and do a little more of negative Leafiness. Now the other part of the equation is when the Leafs are crappin the bed and the local Leafs media tells the truth and reports accurately, LeaFlanders treat it like a Justin Holl turnover, in that they lose their collective minds and immediately bring out the "Leaf Hater" badges for those media people who would dare stray from the fold.