Not quite, because as I pointed out in my first reply, public opinion does not affect whether someone gets unbanned (or banned for that matter). So I would amend your statement to: it's just about whether the people who run the server still care about his past actions.
As I said before an essential part of lifting a lifetime expulsion is weighing the risk of further damage against the small benefit of having a player return. Note that this is an entirely "selfish" question, for lack of a better word. It's not about whether the person deserves to have it lifted. Once you get expelled you've already used up all your chances so we're past making decisions based on whether someone should get another chance. Also note that this is a fairly cold and calculated decision. In other words: that's what we do when we personally don't care and are fine with allowing someone back.
The other option is of course that we do care and personally do not want that person back on the server. If that is the case then there is nothing you can do really. You can't force people to forgive you by arguing that they should. We try to run our legal system fairly by offering the same chances to everyone (as best as we can manage). Even if we don't like them, we will give them those chances because they should get the same chances as every other player. After that, you're basically asking for a favor, which by definition means you have no right to insist that it should be granted.
Do I think your childhood mistakes should follow you around for the rest of your life? Of course not. Get out there and have a great life unimpeded by what you did here as a teenager. You're not in prison nor would any sane person suggest that you should be.
But, in this tiny corner of the internet, you have managed to piss off some people so much that they never want to deal with you again. And whether you agree with that or not, they have every right to choose not to deal with you again. Just like you have every right to do that with anyone who sufficiently pisses you off. Even if they were "only" 16 when they did it.