It's not about telling other people how they should feel, it's about managing your own emotions as an unpaid maintainer of a somewhat public good facing unreasonably entitled members of public (often not even users of your product).

I'm a little confused at this comment, because the person you're replying to didn't say anything to the effect of what you're arguing against here.

That's not the argument. No one is asking users to be grateful for OSS. They just want users to not be dicks to the maintainer.

Would you continue volunteering if the beneficiaries spat in your face and cursed you out for it?