Sad to say I have heard the same - YVR-MAN was a surprise to my local country head.
His words paraphrased - "Manchester - Toronto is pretty much the ideal Rouge route. Seasonal, leisure, VFR."
So why MAN-YVR?
A flight from MAN to YVR does not add a significant number of new destinations to MAN (or YVR) that would make this flight worthwhile. Where can pax go beyond YVR?
And if MAN-YYZ is only at 5-6 weekly on Rouge in high Summer - Toronto is by far Canada's largest city - how on earth would a 5 x weekly 777 to YVR work?