Perhaps deliberately modest marketing would work better at attracting the right kind of users?
If those users are mad because you won't do free work for them they are entitled jerks.
If those users are mad because your marketing made promises it doesn't keep and they wasted their time learning/installing/integrating your project based on lies, you are the jerk.
Some open source projects are aware of the number of users but focus on getting contributors, so that they can make the product better. They are sharing the workload of solving a common problem so others can stand on their shoulders.
Some focus on user numbers, because then they can be famous, or they have a connected business that will make more money.
These are groups that will work very differently and respond to users differently. They have simply chosen similar software licenses.
There isn’t space for an infinite number of libraries in a niche. So if you show up you are occupying space that someone else can’t. Sort of like if your friends throw a party and you decide to throw one on the same day. Kind of a dick move if you don’t have a really really good reason (like it’s your birthday).
Additionally is nearly impossible to sell a library now. It wasn’t always that way, but that’s the world we live in now, in large part because of FOSS. Writing it in-house or using FOSS are pretty much my only two options. So FOSS has to be some significant fraction of the quality of a commercial alternative because we can’t have those anymore. Without any attempt at sufficiency, FOSS effectively makes the world a worse place.
As a user, I have no longer a way of knowing whether an "open source" project's main developers are doing stuff in their free time or on company time. So, I don't see anything wrong with asking for features. Asking for features is how software evelves, whether closed source or open source. If you have a problem with it, put a disclaimer "unmaintained" in the README.md (because not wanting to tirage requests amounts to not maintaining the software).
He didn't discard the notion of non-paying users asking for features at all.
Edit: typo
The best remedy I find is to know exactly where I stand. Is it something I am interested to work on? maybe, if enough users show interest. Or maybe not. And then communicate clearly to set the expectations.
Want this feature? Sure, either do it yourself or hire somebody from freelancer.com or something. Or at least help me refine the requirements from your vague "this is not working exactly like I want". But yeah, even that is taking energy away.
Related to that, I wish github had an auto-close issue feature that would be triggered if the user hadn't replied for a month.
EDIT: but I also get a lot of really good and respectful feedback. I don't want to push these people away because of my previous snarky comments.