There were variables in favor of each location.

Mexico v Canada was arguably a more interesting match to El Tri's fans in Seattle than Mexico v Martinique was to El Tri's fans in Denver. Having been at the matches in Denver that day, I'm certain there were more Canadian fans in Seattle as well (although admittedly likely fewer than would have attended if the match was on a weekend).

The broader point I was trying to make was that Denver's interest in international soccer relative to Seattle's (or other cities' for that matter) shouldn't be measured solely (or even predominately) by interest in their respective MLS clubs.