I mean he's not a leftist. I'm ignoring the constant sexual harassment and latent homophobia that seems to permeate the entire show and pretty much every character here and also that he's like a huge dick, but all his criticisms of people, the system and the world are oddly leftist. Never really noticed when I watched it back in it's heyday.
The final episode really ruined the show entirely.
spoiler
The total fuck you of undoing robin and Barney was unforgivable