@KamiRappa I hope I don't misunderstand you, but: If you get the impression that a minor reviews your "A"-rated works (and you can present some semblance of evidence), you can report* the reviews in question and they will be removed.
In doubt, you can pick a Review Moderator and ask them for assistance via PM:
https://www.newgrounds.com/wiki/help-information/site-moderation
* The little button with the Flag-icon.
Yatsufusa
You can delete 'comments' with the little cogwheel and 'News/Blog Posts' with the trashcan.
Hope that helps. If it's 'doesn't', feel free to delete this comment. ;)
Either way, thanks for caring. (Hopefully there will be an option for users to set a flag in their profiles so that they will only be accessible by users who aren't minors at some point in the future. For now, all we can do is wait and inform others the old-fashioned way.)
KamiRappa
Well, when I say there's no way to delete comments, I was referring to my actual art posts. I assume it's to avoid people deleting negative reviews, but still.