Ask HN: Why can't I comment on old Apply HNs?

When you go to Apply HN, it show a random sampling. I clicked one, and then clicked through to their site. I liked it, but had some feedback I wanted to give. When I returned to the HN page, I couldn't comment.

I assume this is because the page is 20 days old. I think it makes sense to close an old new story, but not for Apply, especially with the random functionality. As a founder myself, I would definitely want to continue to receive any feedback people were willing to give. Can that happen?