They have control over that aspect - that's the point. It's quite obviously not "because I don't want them to", it's because the people who voted for them won't be affected by the decisions they make.
Lots of people had a problem with it, it was just politically easy to ignore it because the establishment of the Scottish Parliament coincided with a strong Labour majority, both in the country and in Scotland, so it made no real difference. Now, evidently, it does.
And personally I'm happy to devolve as much to Scotland as they want. But right now, Scotland already elects people to decide whether they should be able to hunt foxes with dogs - why are their MPs telling me whether I can or not? You're really reaching if you actually think this is a justifiable way for a parliamentary democracy to function.