"Passive aggressive" does not mean "avoids confrontation." Nor does it mean "disagrees with me." Nor does it mean "disagrees with me but doesn't fight about it." Nor does it mean "disagreeing in a way to avoid being the bad guy."
It does avoid confrontation, but it's a very particular kind of avoidance. Passive aggressive is when a person disagrees but says they agree, and then actively but secretly tries to undermine the purported agreement.
For instance, your girlfriend wants to go to Maui on vacation, but you want to go to Miami. Leaving a long-winded letter to her saying you don't want to go, or posting to LiveJournal that you don't want to go, and then avoiding the girlfriend for a month so she can't disagree, that's not passive aggressive. It's passive. It's non-confrontational. But not passive aggressive. Telling her you'll go to Maui, but then fixing it so you "have to work" or "losing your tickets"... that's passive aggressive.
If the person disagrees with you such that you know they disagree with you, it's probably not passive aggressive.
This is mostly directed at the Stranger writers and SLOG commenters, but I see it on my friends list on occasion too.