It sounds right from a tech speak. But the question remains if he will treat the paid customers with this same attitude.

So to summarize

1. You don't have anything better as a term

2. It's a valid and well understood term on the board you're on

3. It's a legitimate problem for those with finite resources

That leads to the conclusion that you probably don't pay for things often which is why you got your feelings hurt. There is literally no way that term should be offensive to you unless you abusively take advantage of services and then some then when it comes time to pay.

An internet summarizes and makes a well informed conclusion :-

Which is, I probably don't pay for things and felt hurt when I saw "yet another paid note taking app" amongst dozen others on the internet.

None of your comments have been relevant to the app. Your comments been complaints about specific verbiage used to describe a particular problem, common to startups, that the dev wished to avoid. We'd love to hear your points on what the app could use, however you've done nothing but insinuate that the developer doesn't appreciate his users because a particular word choice caught you wrong. I can see no other reason someone would take offense to a word choice unless they were personally offended. Please feel free to enlighten us by refuting any point of my comment. Your reply realistically doesn't do anything to respond to my summary.

It is relevant. To answer your question, the app could use a developer with more humility towards users.