Of course, as far as she's concerned, having to hit more than one button to turn on her computer is just strange and a little silly. She might very reasonably think, "That's stupid, is there some OTHER time you'd want the computer on, but the monitor off? Or the monitor on but not the computer?" This would be (to her) like having to turn your television on, and then make sure you turned on the screen. And, remembered to turn on the speakers, too.
There's nothing unreasonable about her reaction, in fact, having all these separate power buttons is the real loser idea. Most of us here just take it for granted when it is really pretty stupid.