Tough old cowboys ain’t always what they seem in this simmering tale of lust, duplicity, and alienation — but then, who is? — This article spoils the movie like toxic masculinity spoils a potentially hot roll in the hay. No secret goes unrevealed. Watch the movie first. “What kind of a man would I be if I did not help my mother — if I did not save her?” Power of the Dog is one hell of a movie, in which nearly everything of consequence goes unspoken. Indeed, it’s a movie about the fact that…