> Just in the same way you can't harass someone in the street
It happens all the time. People harass other people, begging, wanting you to fill out surveys, trying to sell you stuff. Go down a pub... Look at football supporters harassing each other. People need to grow far thicker skin when it comes to words.
> there shouldn't be carte blanche for bullying just because it happens to be online
Online "bullying" isn't really bullying though. It's your computer telling you that some human being apparently said something. You should take that with a huge grain of salt. It could as likely be a bot. It's parents place to educate their children into the mindset of assuming nothing is real online. People are not who they say they are. People may not exist.
Am I being online "bullied" by the automated spam process sending me emails suggesting I need penis enlargement devices?