How do you explain...?

[Zombie]

My guess is that they're used to reading WoW weapon speeds.

This. In WoW, your weapons are shown as "seconds per attack," and in Diablo III, "attacks per second." It's probably throwing them way off.

This is what I thought of too. Most games I seen got seconds per attack or damage per second in that spot that attacks per second is at. It's like if you read one of those sentences where all the letters are messed up, but like, you can still read them cause your brain can rearrange the letters. Some people just see what they're used to until it's pointed out to them that's it's all messed up. He probably played a lot of other games where it's the other way around.