I first overwrote them all with random words, then with an explanation of why (reddit API protest, and superstonk censorship, mentioning whynotdrs). Woke up this morning to find I'm perma-banned :). They don't want users attempting to call attention to other communities:

Hello, You have been permanently banned from participating in r/Superstonk because your comment violates this community's rules. You won't be able to post or comment, but you can still view and subscribe to it.

Note from the moderators:

You've chosen to attempt to pillage this community to build another. If there's another community you'd rather be part of you're welcome to go there instead.

If you have a question regarding your ban, you can contact the moderator team by replying to this message.

Reminder from the Reddit staff: If you use another account to circumvent this subreddit ban, that will be considered a violation of the Content Policy and can result in your account being suspended from the site as a whole.