I see value in a feedback mechanism for raising the bar of top voted submissions. Since posts aren't downvoted flagging is reserved for other use, what other acceptable means is there for providing this signal? At the same time, if there's not already discussion on such a post, even a negative one is engagement which could further popularize it.
Another thing I've started doing is being more liberal with my upvotes to get them above the floor of low-quality post scores.
Does this seem like what's happening and a fine way to approach it, or should something else or nothing be done?
Now, when to pass along a bit of feedback is a judgement call only you can make, but I think in most cases people will also learn by trying and failing.
Your OP is the same OP that has been posted hundreds of thousands of times by this point, on different forums and usergroups. And the answer is the same as it has always been: Drown out low quality content by posting high quality content.
My belief actually is that visibility of posts is suppressed if they get, say, 20 comments and already have 50 votes.
So if you want to be systematic about posting comments with some “tough love” go right ahead.