In terms of Seattle being easier, I believe what the writer was referring to was that for him, as a Canadian living in/near YVR, it is significantly less expensive to fly out of Seattle, likely due to the costs imposed upon canadian travellers by the government and air canada's high cost structure. Plus the lack of competition on international routes.
I've heard some people from my hometown of winnipeg drive down to grand forks, north dakota because they can save a significant amount of money vs flying out of ywg on ac or wj.
Same for southern ontarians using buffalo as a gateway airport vs pearson.