They aren't pestering the developers; they made a comment on HN about what, to them, is an essential feature of a note-taking app. The developers may never see it.

I happen to agree with them. The single most important aspect of a note-taking app is that I must own my notes. That means that I must be able to take them elsewhere if I want. Including, in fact, especially, if the company hosting them goes out of business or simply chooses to discontinue the app (looking at you, Google).

If I can take the plain text but lose the formatting or the cross-linking, that isn't good enough (hello Google Keep export).

But if lowercase can find enough customers who don't feel this way, all power to them.