Vast majority of users are not capable of recognizing that such comments are spam.

That sounds like it is not a problem then. If the author of the post does not have a problem with the comment on their post, I see no reason we need a third party to act as an authoritarian on the issue.

The problem is that spam posts simply spam the Blockchain.

That was dealt with by RCs. Again, you are creating an authoritarian state on a supposedly decentralized protocol and making rules for users that you do not follow in your own operations. RCs were meant to manage spam, creating a cost per action. If a person is willing to cover the cost by investing enough in the network they have purchased their right to said actions.

You are forcing your own ideologies about what should or should not exist on a protocol that is suppose to be about freedom of action and expression. This is why the Steem experiment has revealed that unlimited stake weight is a bad idea. Unlimited influence over the network by a single entity leads to centralization and authoritarianism.

I thought, perhaps mistakenly, that your earlier comment was suggesting you would be relieved to not have to bother with "spam" comments. It now seems that it was a bluff because you assumed I cared that you did that job... I don't. However, I support you in hunting down scams and obvious and proven plagiarists. (read: not just people that don't check in with you, which happened to @jsecoin's original content)