Believing that other people knew (or should have known) how angry they were going to make you is exactly what makes outrage-driven discussions blow up.

Malice and spite exist, but I think they're very rare compared to incompetence.

Also note that doing things even when you know that they will make other people angry is not necessarily malicious or spiteful. In most cases it will be because healthy individuals place limits on how much responsibility they assume for other people's emotions. Doing things because they will cause another person could be spiteful. (Although even then that is not necessarily the case. See, for example, the recent Star Trek movie in which time-travelled Spock tells Kirk to provoke an emotional response in the young Spock, allowing Kirk to save everyone including Spock.)