Oh?
So passive aggressive anger like say Sean's is OK but just blast it out like Md's isn't?
How's that work anyway?

Not very nicely, however passive aggressiveness can be less disruptive and less destructive to an entire group, more like targeting just one person or process. Passive aggressiveness can also exhibit less offensive pride/arrogance.
Now, I know what you're going to think. You're going to think that because I highlighted two sort of better things about passive aggression than aggression that you'll think I'm condoning it. Not necessarily.
Especially in the dependent elderly, playing dumb, as you probably know, can be a form of passive aggression, so when that happens, it's good to patiently find out what actually is causing the aggression and deal with it. However asking questions, learning things, having dementia, or exploring gender roles is not truly playing dumb.