Recently I had a user spamming the channel forum, and was also sharing what appeared to be some objectionable (to me) media.

I don't often use my god powers but when I do it is likely to ban.

My understanding is that only the OP can remove a post to the forum. However, I have been informed that if a user is banned, any posts to the forum will be unshared, in effect, deleted, removed.

I clicked on the objectional post, then set user level to banned. Nothing happened. The red X did not appear that I had observed at other times.

I tried over and over and when I saw that user online in the channel, I set their level to ban again. Nothing happened.
I cleared bans and tried again. Nothing.

I then cleared the userlist of most offline names, starting with those that were not advertising shares.

After that, I could ban the creep.

It appears to be perhaps a matter of scale and the user history has limits as does perhaps the ban/permission list.

If that is it, the limits are to small for large channels.