Am I in the wrong?

Me (17) and my boyfriend (16) have been dating a year. I'm 17 and have my life set kind of straight. I know what I want. I'm getting ready for college and I've never felt the need to do stupid things that might prevent me from doing what I plan with my life like drinking, drugs, and other illegal things. I believe all about experimenting with life because you only live once right?

Well my boyfriend is a complete straight edge. I'm not against marijuana at all. (Whoo legalization!) but I've never smoked it due to getting in trouble with the law or it being laced with other things. My parents smoke it and it's never been an issue. Drinking isn't an issue to me either. I belive if you're being responsible, then go have fun. Well I've talked to my boyfriend about not being against it and he said he'd break up with me if I did either of those things.

One time on my birthday, a few months ago, I asked my mom if I could try a beer. I was all around family and no one who wouldn't be able to watch me was there. I'm the state of Wisconsin it is legal to let your child drink alcohol if you let them. She said yes and I had like 3 sips. My boyfriend was there and got so upset with me and he eventually left the party. Beer never got finished because I felt so bad. He eventually said I would end up like my mom if I kept drinking.

On the 20th, his parents left for vegas. He was left home alone with his 19 year old brother, him self, and his 13 year old brother. Rules were normal rules. No girls, no drinking, no parties, no fires.

Well his brother invited a few people over, like 7 or 8, and they played DnD in the basement (a role play board game type game). They weren't doing anything wrong. It was not a party let alone by all means. Well he brings me over to his house to hang out (Breaking a rule) and he talks about his brother is having a party. I say well it's not really a party but I just let him talk about it. It's not worth a fight.

Eventually his grandpa comes over to check in on the house. I was upstairs and my boyfriend was downstairs. His brother and his friends were downstairs. Boyfriend runs upstairs and says "I just saw one of my brothers friends with vodka and my grandpa just got here" and was like laughing. I said " do you just want to get him in trouble or what?" He said he hope he got in trouble for it. The grandpa never found out cause he left pretty soon after and I asked my boyfriend why he wanted to get his brother in trouble. He said he hated his brother and he said they're all underage and they shouldn't have alcohol.

While I personally believe that yes, it's irresponsible that they have alcohol, I don't believe he should go out of his way to get them in trouble. He eventually starts to say he wants to text his parents. I say "dude you dont have to do that just let him have his fun" and he gets mad at me and says "well it's not right he's not following the rules". At this point I'm just kind of annoyed that he would worry his parents on their vacation just so he could see his older brother in trouble.

Soon after that his little brother comes up the stairs and my boyfriend asks him if he knew they had alcohol. His little brother said no I didn't but I don't really care. And my boyfriend literally says "well you're not going to drink with them are you?" And his brother got upset he would think that and said "No! They probably don't even have any alcohol you're lying."

Here's were things get bad. My boyfriend got upset his brother didn't believe him and said "Watch I'll fucking show you they have alcohol." He storms down the stairs and goes up to the kid and says "do you have alcohol!?" And the kid goes no I don't have any alcohol and opens up his bag to show him. The kid was hiding it in the back so my boyfriend thought he had the right to pull out everything in this kids bag (he's never even met this kid before) and pulls out the vodka and said "yeah well what the fuck is this?" Kid is like freaked out and was like umm I'm sorry it bothered you that much I'll bring it home. And he did immediately. Boyfriend completely lost his shit about it and was talking about he was going to tell his parents.

At this point everyone was pissed at him for making this scene and they weren't happy with him. Everyone then left his house and me and his younger brother sat there while my boyfriend stomped across the house "cleaning" and talking shit about how everyone is a pig in his house.

I was really upset my boyfriend acted this way towards his brother and his kid. His older brother eventually told his parents what happened and my boyfriend of couse had to make sure that his parents knew he was the one that kicked the kid out and how everyone else was fine with it. He really only cared about him at that point.

Am I wrong for being upset at him about this? He just can't live a little.