>Why the hell should I clean up the mess created by my classmates?
Isn't that the entire point? To teach you that the "someone else" who cleans up your mess is actually one of your peers, a person just like you.
Asked another way, why the hell should one of your classmates clean up your mess? The answer to both is you shouldn't leave messes for others to clean. Making kids clean up messes from their classmates teaches everyone to clean their own mess.
Whereas in the US, all schools have a janitorial staff. In general, janitors are looked down on as the absolute lowest of social class. It creates this mentality of not giving a single fuck about the mess you create because "someone else" will clean it up. And because they're a lower social class they somehow deserve the mess you make.
Yours and chii's comment make me think that this is a more subtle and cultural thing. I'm a bit surprised that you believe peer pressure works like as expected. (Don't take this as an offense, I'm genuinely surprised).
This is a classic example of 連帯責任(approx. same as collective punishment), which is very common is Japan (and in other countries too, I suppose).
This doesn't work, because the mess you make is not the same amount as the others make, and the mess you clean up too. Thus, the system effectively incentivizes you to make more messes and let others clean them up. 正直者が馬鹿を見る(The honest man loses his money).
What actually happens is, some jerk shits, forces others to take care of it, and the jerk never cleans up. In short, your "janitors" are just replaced by poor bullied kids. (I'd rather say, it is a system to bully these kids. I believe you can find some examples from the Imperial Japanese Navy).
If I put my 2 yen, the only system that works is that those who made a mess clean up the mess. A system that can be abused will be abused.
Isn't that the entire point? To teach you that the "someone else" who cleans up your mess is actually one of your peers, a person just like you.
Asked another way, why the hell should one of your classmates clean up your mess? The answer to both is you shouldn't leave messes for others to clean. Making kids clean up messes from their classmates teaches everyone to clean their own mess.
Whereas in the US, all schools have a janitorial staff. In general, janitors are looked down on as the absolute lowest of social class. It creates this mentality of not giving a single fuck about the mess you create because "someone else" will clean it up. And because they're a lower social class they somehow deserve the mess you make.