I'm not sure how that disadvantages you. You get paid for the time you work. Seems fair to me. So you have to stay a little extra and be bored if there's not enough work rather than being able to go home early. Boo hoo. For every one of you, there are ten people in the U.S. that get asked to work 45, 50, 60 hours a week for the same salary they were getting for 40 hours. Now that is to the advantage of the employer. You sometimes don't have enough work to fill 8 hours and have to sit there and be bored? Cry me a river.

I much prefer to (and currently do) work salary. I like being able to go home early when I finish my workload ahead of schedule, just like you. And I'm fortunate enough to have an employer that doesn't demand more than 40 hours even if the workload is high. But when it comes to employers taking advantage of and exploiting their employees, a salary structure can be far more exploitative than hourly wages.

Now, for hourly workers, reducing them to part-time and hiring twice as many people as you needed if they were full-time, so you can avoid having to provide the benefits that are required for full-time workers (health insurance, etc) -- THAT is the way to expoit hourly workers. Not making them sit at a desk twiddling their thumbs in order to get an extra hour of pay, that's not exploitation at all. I'd be thanking my employer for letting me do that if I were you.