I don’t see a problem with making polite observations about aspects of the content that makes it to the top.

If this isn’t a place to discuss the submissions, what is it?

Discussing is obviously fine.

But sometimes some innocent blog posts get criticised as if they claimed that they solved world hunger. They don't. They are often just some random thought in a rarely-read blog. Nobody intended to go convince a gang of seasoned hackers that they have undisputable wisdom.