I blame the Internet culture of the late 90s early 2000s. Referring to your customers as Lusers and dismissing their "dumb" questions was all the rage amongst a group of nerds who had their first opportunity to be the bully.
I think this "first opportunity to be the bully" thing is spot on. Everybody learns from being bullied. Some of us learn not to do it when we have power; others just learn how.
