1. Fine, "mature" was a poor word choice. The kid should still be better than to hurt people unprovoked.
2. So you were that one guy who was shouting for peace after Pearl Harbor? No, virtually everybody wanted to go to war because everybody knows that if you let somebody walk on you without consequence, they're going to keep walking on you. It's the same idea as punishing people for committing crimes. In your fictional world where nobody believes in retaliating against injustices, there would be no such thing as a courts or prisons. Like, how stupid must society be to think that people should be punished for stealing? That's so middle school.
3. Confiscating and stealing are the same thing. The brother took his property without permission. That's the definition of stealing. I never said he should press charges against the brother for stealing from him. I simply stated that the brother ought to be held liable for his crimes, and he is lucky that he won't be.
4. Your supposed question was "are you 12?" Don't pretend like that was a legitimate query. It's common in internet arguments to say "I don't like your argument, so I think you're a little kid." Simply asking if I'm 12 is just a way of rephrasing that sentiment.
5. You called me stupid multiple times. If that isn't an insult in your book, I don't know what is.
6. You're using the word "lucky" in an overly literal sense. He most likely would have taken any substance away from them that he thought the parents wouldn't let them use. If they had been smoking cigarettes or salvia instead, the kid probably still would have stolen them.
7. If he wanted to eject OP from his property, it's more than within his rights to do so. He, however, has no right to steal from him just because OP is on his property. He could have easily told his parents or kicked him out of the house himself without stealing the weed, but he didn't. If my sister brought her friends into my house, and they started doing cocaine together because I'd rather have them do drugs in the safety of our house than out on the streets. But even if I did want to kick them out, I wouldn't steal their drugs. If she brought her friends into my house and they started playing loud music when I didn't want them to, that wouldn't give me the right to steal their stereo.
Seriously, for everybody else, hitting the shift key is second nature. I do it with no extra effort. The fact that it's too much of a bother for you to do it at all shows that you're not only really lazy, but really stupid as well. You're too stupid to do it naturally, and you're too lazy to force yourself to do it. Pretty shitty combination of traits I must say.