Let me get this straight. HN has a mechanism to deal with abusive users. You deliberately disabled that mechanism so that you see posts from abusive users. And now you're complaining that you see posts from abusive users?
There are reasons why HN allows the "show dead" ability and probably none of those reasons have to do with people trying to punish themselves by seeing "abusive users'" posts.
If hellbanning is being abused, then that should stop. Adding a second banning mechanism doesn't seem like a useful fix.
That means, that by you turning on dead posts, you are subjecting yourself to the 80% case where they get it right. If one of them is spamming with huge blocks of text, etc... well, you signed up for it in the low-probability case that one of the dead posts actually contained valuable information.
Keep it simple. Don't start adding multiple layers of hellbanning protection just to fix a low-probability edge case.