He's right, that's not a prank. If I went up to you and started yelling at the top of my lungs and started cursing at you, is that a prank?
Now if I played a practical trick on you, then that's a prank. The prank can involve a person being an asshole, or playful, but the bottom line is that it has to have some sort of joke in it, not simply ****ing with people.
Random prank
https://www.youtube.com/watch?v=aK6BUj9iAOU
This one is a prank call that gets the other person mad, but again it's not because the prankster is simply calling him names to get him mad, but rather he's following a set up for a reaction
https://www.youtube.com/watch?v=HpolEwL9NpI