rudeness is unacceptable, but there's also the belief that if someone is working on open-source, then any type of a complaint about the software is unwarranted. That actually itself is entitlement. No matter if open or closed source, sometimes customers are going to complain.
>customers will complain.
Assuming they are paying customers and not users. There's long been the attitude that the developer is doing people a favor by not charging for using the software and therefore 'if you find a problem, fix it yourself using the source code'.