Having maintained an Open Source project for almost 20 years now, there are some ways to deal with bad users.
One is to not take it personally. Annoying people should get ignored or banned. They're just not worth the effort.
Two, is to recognize that your time is limited. If the person filing the bug can't (or won't) help track it down, well... too bad. Maybe no one else runs into the bug, and your best response is "works for me". (Note that this is the approach taken by most commercial software vendors in my experience)
Three, is to recognize that there are idiots out there, and you can't help them all. It's OK to be on the lower end of the bell curve, but sometimes it's like the kids rides: "You have to be THIS TALL to go on this ride". If the user can't comprehend something, perhaps he shouldn't be using it. And perhaps you shouldn't waste your time trying to get him to understand something he just can't understand.
My general approach is to be nice to people who ask good questions, and who try. When people ask terrible questions, and make it clear that they have no interest in lifting a finger, but demand that you do all of the work... well... they get told in no uncertain terms to shape up, or get banned.
You don't owe these people anything. If they had an ounce of human decency, they would understand that they got the software for free, and that they don't deserve anything. And that they need to put some effort into it on their end.
The main response I have with these people is If you're too lazy to help solve the problem, then I'm too lazy to help, too.