The links in the submission text are not clickable. It's one of the 100 tricks that use HN to encourage some types of submissions and encourage other types.

For example, the idea is that most people should post the URL and then add a comment, instead of posting a personal opinion with a link at the end (like some posts in Slashdot).

But the post where the submitter is the author are sometimes an exception. I think it´s fine what you did here.

In some cases the mods press the magical button to make the link clickable. The exact conditions are not clear, it's part of the secret sauce. Perhaps it's automatic, perhaps it is manual, or perhaps it is a combination like "when the post has at least 20 upvotes but less than 3 flags, or when a mod mark it manualy".