Couldn't have said it better myself. In the real world, most people are civil to each other even if sometimes they curse others in their head. As long as they don't act on it, that's not passive aggressiveness. It's just conducting yourself with the civility of a human being.
For a long time, the internet and online gaming especially has offered a way for people to be anonymous, and thus gives them an outlet to act like an asshole. But I have a question for people who want to be openly toxic:
If your real name was attached to all of your online personas, would you try to avoid being a complete dick to other people who also had their real name displayed?
The answer most would give (honestly at least) is likely not.
Passive Aggressiveness is not cursing someone in your head. Passive aggressiveness is where you do or say things to subtly show your distaste for someone. Passive aggressiveness is acting on those negative emotions but in a more subtle way. If nobody acts on toxic feelings and remains quiet. That's not passive aggressive. That's just staying quiet about your feelings.