I don't think anyone here likes spam postings. Or links to malware. But how can MikroTik police what is posted?
And what about the useful topics like Rextended Fragments of Snippets that may contain techniques that could be used in a malicious way.
What about posting links to github repositories that may be totally safe (but how can anyone really know)? A recent example: Export config in a readable format
What about posting links to external sites (like the one I recently discovered from this post) that is to a site that looks very useful to me http://mikrotikdocs.fyi/, but it seems to have disappeared, and isn't on the wayback machine. That's a shame, it was useful.
So, I can't vote for blocking advertisements, without knowing exactly what you mean by advertising.
And at least on the forum, if someone does post a link to something that is malicious, it is likely to get responses and will probably be "reported/flagged" for moderators to deal with.