Just like there's no ethical consumption under capitalism, there is no ethical voting under a two-party imperialist capitalist state. The only thing you can do is choose the least bad option at every opportunity you get. And sometimes that means voting for bad people
There's almost a point there, but at the same time if you constantly defend your voting choice and act like it's extremely important, especially if it's a vote for the president, then something's gone wrong with your ideology.
The best thing to happen to Canadian politics is the Bloc Quebecois. Even in a FPTP system, Quebec achieved regional representation (which is, of course, why Quebec gets disproportionate amounts of government support).
The US lacks that. Canada's democracy is still fucked, but at least smaller parties can survive.