@svenja Some people have argued that it helps reduce clutter and brings issue counts down to more manageable levels for developers. I think that's an invalid argument; the bugs don't go away just because you close them. You're just pretending they do. It's fine to say "we don't have the time to fix all of these things", particularly for volunteer projects, but I don't understand why you'd want to delude yourself that there are less bugs than there are. If my project has 5000 open bugs, that's unfortunate, but that's also life.
@jcsteh Yeah, also this. I'd rather see them saying "we can't reproduce it" than just closing it.