I don't think that's true. It appears you just assume that because pull requests cannot be disabled on GitHub.
Sending unsolicited pull requests to people that clearly told you to open an issue first is disrespectful. You don't have to engage with a project or a community, but if you decide to participate by submitting a pull request, you should follow their contribution guidelines.
The healthy maintainer-side attitude is that these impose no obligation whatsoever to review, apply, or even look at, the fork in question.
https://docs.github.com/en/communities/setting-up-your-proje...
The emotional side of the burden of closing PRs which don't follow guidelines is the part which can be set aside. It's just a bit of housecleaning, it's seldom done from malice, English is not everyone's first language, etc.
Getting upset that a mechanism which exists and won't change gets used is not healthy.
You do you. I do not think it is, and so far nobody has made an issue out of it.
> It appears you just assume that because pull requests cannot be disabled on GitHub.
It’s more that people that make a public repo on Github and expect no pull requests on even mildly popular software are living in fairyland. Don’t make a repo on Github when you know PR’s can’t be disabled. Or I dunno, install a bot that automatically rejects everything.
You have the option to walk away and not contribute if you don't like the rules for interaction that have been set by the people that manage the project. Or just follow the rules. Those are your only two sane options, unless you become a maintainer yourself at that project, and modify the contribution guidelines.
To be very clear, you have to understand what NO means in this context, and realize that "I don't like bureaucracy" is not a valid reason to push forward on your own terms.