Well one is some brilliant mature individuals will lose some career opportunity's. Like say a guy goes to apply for the job of his dreams only to find out hes too young. They only want adults. Yeah he could try later, but some dream jobs only come once.Give me a reason besides "some people will be upset" and I'll consider it. .
Also it wont solve anything, ppl will still drink. Just will make it harder. Will this make them more mature and responsible? No!! Will probably have the opposite effect. So why would you want to raise it then? I just don't see a reason to raise it, seeing it won't solve anything. Just will infringe on young ppls basic rights.