What if someone harassed/insulted/calling names in a comment, but an admin won't do anything about it because the comment was 2 months old? What can you do?

I tried reporting someone who had done that, and the admin won't do anything about because, in his words 'I'm not going to do anything about a comment that's two months old unless it links to illegal content or malware.'

I don't recall seeing that part in the Harassment rules section.