Doesn't matter what the source is, if an ip is spamming it will get blocked automatically in the future
Discussion
Maybe ban IP is not a good way, there is the AI method to recognize spam content, ban spammer pub key if they send content fulfill the model.
We already solved this with PoW, just make accounts pay to post. First 20 per day are free, then price goes up exponentially
It could be implemented simply as a client feature.