All of the arguments in this thread are invalid as of now.
Comparing LoL and SC2 specifically in terms of skill is ridiculous. They both are entirely different in where their skills are derived and comparing them is pointless. StarCraft is meant to be a single-person strategy game whereas League of Legends is meant to be a multi-person battle arena. In StarCraft skill is measured on the performance of a single player, whereas League of Legends it is measured on the overall performance of a team.
Comparing them both is like comparing American Football and Wrestling (not the fake kind) and trying to say that one is harder than the other. While they are both physically demanding, they are very different from each other. They both can be difficult in their own way. If the players on the football team do not play well together, they will not succeed. If I wrestler does not perform well for himself, he will not succeed. However, notice how whenever a player switches to the other sport it is no longer as simple and easy?
The same goes with these two eSports, the transition between them is not as smooth as you'd expect. While StarCraft is more mechanically demanding and APM intensive, it doesn't mean shit if you can't work as a team and don't know how to build your champion properly. This goes without mentioning last-hitting, combos, etc. Yes, there are less buttons to press, but that is to be expected in a MOBA. This can also be turned around, while LoL requires vital teamwork skills, it doesn't mean shit if you can't strategize on your own in real-time, have strong mechanics, and highly refined micromanagement skills.
If you're going to compare the two, compare them for the games that they are and if you do or do not enjoy them. The argument of skill is neither comparable, arguable, nor relevant.