I used Power Delete Suite to edit then delete all mine. Just bookmark the big red button and open it on your profile page. From there, you can tweak it a little before it nukes everything.

I saw a comment from someone asking people not to do this, even if they're pretty unhappy with Reddit. The reason he pointed out was that many people across the Internet benefit from the content in comments being available. Blowing that off the Internet is going to hurt people who are looking for information.

I think that that's a fair point.

I was never especially enthusiastic about expertsexchange.com. But I have definitely gotten useful information from it, and it being made inaccessible would (looking at the domain, did) disadvantage me.

Also, even if one is concerned about reducing value to Reddit as a company and one considers that to be an overriding goal, if I recall reading a past discussion correctly, deleting a comment doesn't, as I recall, wipe it from Reddit's database. It just hides it in the web interface from other users. That doesn't mean that Reddit can't use it as AI training data or whatnot.

If Reddit does a Digg-style implosion over this, then I think that the loss of the active userbase is probably a sufficient disincentive. That's something that cannot be easily replaced. And that doesn't disadvantage other users on the Internet: it just means that new content will be available on other services.