Wow, I didn't even know there was the option to block comments! ::: crawling out from under my rock::::  
I agree with you. In fact, I was just going to post to ENCOURAGE comments on songs.  While the forum is valuable in regard to asking for/receiving feedback, personally I like comments made directly on the writer's page & song.  Another music platform (I won't name) offers listeners the opportunity to give comments on a song as it plays out on its timeline -  ("wow, love the transition into the bridge here!", "beautiful harmonies", etc). You can see at what moment in time the listener reacted.  Comments are important!  Oh of course there have to be safeguards (community standards), but as a whole, I love the concept.  It makes the performance of the song that much more viable. (sorry for going on so long!) 

Where do you see that? Usually you should not be able to create a comment unless you can actually post it.