I just went to look at Reddit to learn more about this. Someone there makes the good point that if the mods can edit user comments, they could in theory plant false evidence of crimes.
Sorry to nitpick, but I'd like to point out that "administrators" and "moderators" are two different groups in Reddit. "Administrators"(which spez is part of) are Reddit staff; Moderators are users who create a subreddit or are enlisted to help manage it; Moderators do not have the power to edit user comments.
https://i.reddituploads.com/26af29432a2340a98d83052a0ed3efcc...
I didn't understand the significance of this until reading that comment.