> clearly explained in the first paragraph of the readme

Yeah but people justifiably don't exhaustively read documentation. If people are getting confused because they didn't read some bit of documentation - even the first paragraph of the readme - then you shouldn't just dismiss them as stupid and bask in your superior documentation-reading abilities. You should think about how to resolve that confusion in a way that they would actually see it.

It's hard to explain how to do that without a concrete example, but it usually is possible. It's also usually more work than just replying RTFM, but you should at least be aware that you are choosing not to bother.

I'd rather OSS authors write and improve the software and documentation for most people than do the very time-consuming, burnout-inducing free customer support you are suggesting here (especially for those not bothering of reading even the first paragraph of the documentation).