I can understand where you're coming from, @rok-sivante. But said witness is very low in the ranking, meaning he has no real influence. You wouldn't see someone doing similar in the TOP 40 let alone TOP 20 - with an exception here and there like JB.
Keep in mind that nobody is something special for being a Witness. It's just a term for running a program on a server. Doesn't make him automatically a better human being.
And if somebody is willing to promote himself by spamming comments, then he is shooting himself in the foot. That's my opinion on that matter - as a Witness (block-producer) myself.
I cannot agree. I revealed the fact that a high rep user spammed Steemit, and got retaliated by him and his bots. Now the spammer is a top witness. For details please read:
The Dark Hand of Steemit