In Which I Rant (Briefly) About an Undercooked Burger

The hamburger I ordered today at a St. Louis restaurant that shall remain nameless didn't look like that in the middle, but it was much closer to raw -- not rare, but raw -- than medium, as I'd ordered. Now this isn't the first time a hamburger temperature screw-up like this has happened to me -- far from it, in fact, which is why I'm bothering to post this.

Is it really that difficult to cook a burger to the requested temperature in a commercial kitchen?

I don't mean to be an asshole (though you could argue I'm paid to be one), but, really, any ol' schmuck can buy a working meat thermometer. Please suggest your theories -- or call me an asshole -- in the comments.