One's having a bad day does not excuse anti-social behavior. Ever.
In other words: Trying to punish rude users by not fixing the bugs they report is like cutting off your nose to spite your face.
In other words: There exists roles and relationships, with attached obligations and expectations, other than those involving money. Free software development is such a relationship, as is this debate.
There are obligations other than money, but none of those exist here. There’s no contractual obligation. He put out something for free and doesn’t need to take an iota of criticism on it by people freeloading. He obviously can, and if he wants certain goals like increasing his user base it might be the smart move to respond to these type of people, but there are no obligations.
That sounds like a social and/or cultural obligation to me.
If the only issue my application ever had was reported in such a rude manner, there might be a case to be made to fix it, even though it was reported in a hostile or rude manner. It might make the application better for people who didn't report the issue. But maybe it is more valuable to just spend that time on something fun or enjoyable like coding on something else or eating cake. There is no reason to waste your free time on rude people, when they have the option to just be nice and save you all the anger.
That’s a value judgement man. Not everyone values turning everything into a productivity improvement over all other values
To be excruciatingly explicit: Bugs (and confusing UI/UX) experienced and reported by rude users also affect many non-rude users. If one wants one’s software to be the best it can be, then one should listen to all bug reports; the attitude of the reporting users are irrelevant.
I agree that he’d be under an ethical obligation to listen to a rude security report. But it doesn’t follow that he must therefore listen to all rude bug reports.
No Jerks cuts many different ways...
Maybe his wife just cheated on him, divorced him and took half his money, his kids don't want to have anything to do with him, his bank took his house and he just crashed the car. And he tried to use Notepad++ and the same old issue happened and he snapped and sent that email.
99 out of 100 times he would have send the email you mentioned here but he had a horrible day and vented in the email. Does it make it ok? No. Is it understandable? Yes. Should we discard the feedback because he was frustrated? No.