Sorry to be so cynic, but why do you assume good faith on the part of Reddit? It's a free product, you are not paying for it, they don't owe you a damn thing. If they don't care about their reputation, they can do whatever they want with your comments, including changing them or deleting them.

This is the problem of free stuff, you have no leverage and little to no value to the company as a single user, and if you are the kind of problematic user such as the ones in The Donal, you have negative value because you scare away the ads and ruin the companies reputation, so they actually have a very powerful incentive to push you away and make you leave the site.