Often this does come from people that don't write software. Though some of the more grading experiences in this area I have had did come from people with at least some experience in writing software. Where they used that experience as a sort of argument as to why their demand should be met as swiftly as possible.

Do you know what happens if those "demands" are met with a response of: "I don't like your tone, please rephrase this as a polite request and I'll consider it"

There are ways of setting boundaries around behaviour in real life. Can maintainers use those methods for this?

> "I don't like your tone, please rephrase this as a polite request and I'll consider it"

Phrased like that, I feel like things would only escalate. But in specific situations like the ones I mentioned, I would go for something like "As you know from your own experiences, software development takes time and effort and this is a volunteer project. I do take suggestions and issues seriously and am happy to discuss them in a constructive way. This discussion at the moment does not feel like such a constructive discussion. I'd be happy to continue the discussion from a more constructive place" and leave it at that. It is a bit more explicit than just "tone" and also makes it more clear as to why they might want to take their behavior more into consideration.

Overall, yeah I think maintainers and the setup of the project do influence a lot of how people interact with them. I actually left a comment about that somewhere else in this thread: https://news.ycombinator.com/item?id=41188425