You owe them nothing. That fact doesn’t mean maintainers or users should be a*holes to each other, it just means that as a user, you should be grateful and you get what you get, unless you want to contribute.
Or, to put it another way: you owe them exactly what they’ve paid for!
Some open source projects which are well funded and/or motivated to grow are giddy with excitement at the prospect you might file a bug report [1,2]. Other projects will offer $250,000 bounties for top tier security bugs [3].
Other areas of society, like retail and food service, take an exceptionally apologetic, subservient attitude when customers report problems. Oh, sir, I'm terribly sorry your burger had pickles when you asked for no pickles. That must have made you so frustrated! I'll have the kitchen fix it right away, and of course I'll get your table some free desserts.
Some people therefore think doing a good job, as an open source maintainer, means emulating these attitudes. That you ought to be thankful for every bug report, and so very, very sorry to everyone who encounters a crash.
Needless to say, this isn't a sustainable way to run a one-person project, unless you're a masochist.
[1] https://llvm.org/docs/Contributing.html#id5 [2] https://dev.java/contribute/test/ [3] https://bughunters.google.com/about/rules/chrome-friends/574...