Maybe i'm alone on this one, but i'm pretty sure that just messing with people's emotions isn't quite the same as controlling their thoughts.
In the very first book, when Harry accidentally slips Susan the love potion, he's not considered a lawbreaker there.
Lawbreakers are those who take away the free will of another, even if it's just for a single choice. They remove the ability to choose. If you can make one option more attractive than another, then you are not removing the choice, just modifying it. Making someone more emotionally inclined to make one choice over another is not mind-control <i>per se</i>. If it can't make someone go against their nature, or do something they wouldn't have normally done, then it's not really mind control. if it doesn't actually break though the ego barrier that separates "me" from "them" then it's not mind control.
This is just the way I see it anyway.
I think, at the end of the day, it's a combination of the effect, and the means used to reach said effect.
Perhaps just as important as taking away free will is the part of piercing their mental barrier and making them more vulnerable to the things that go bump. I'm not sure if they actually talk about the Ego Barrier in the book, but that's how i see it. It's what separates the Ego (the sense of self) from that which is not ego. One you break that skin, you have a hard time differentiating what is you, and what isn't. Molly's boyfriend undergoes this very type of madness, not sure WHY he's being followed, or why he's feeling what he's feeling.
It's a bit more esoteric, but that's how my little fevered brain sees it.
If you want to be really exact about it, some could say that emotions originate in the body, not the mind. Emotions are hormone and limbic reactions to stimuli. They originate stomatically in whatever parts of the body control adrenaline and the like. Sorry, i'm not horribly well-read on these things.