Answers (1)
Because online, you can be anyone you want to be. Wether it's real or not. Almost like a game, it is a way for someone to escape their real life. also many people act differently online because they don't get the chance to say or do things in real life or because they're afraid of doing it in real life.
There are many other reasons but those are the most common.
Also online you don't have to see another person face to face and they can't tell if you're embarrassed or not.