I looked and I realized that there's no filter that allows you to only see open questions:
I know how to do this in a search (
closed:no). As such I don't see it as really problematic that it would allow you to be "ignoring broken windows".
The main purpose being able to filter closed questions out is to find questions that you can answer right now. It would also be useful from a moderation perspective: I use tag filters to view tags that are "problematic", where most of the questions are either off topic or need to be retagged, where it doesn't make sense to spend time on closed questions.
While filtering out closed questions has been asked before, I can't find any questions that asked about adding this as a custom filter option, which is why I'm posting this. (In the earliest mockups of the feature it looked like this was going to be possible, but that changed somewhere along the line.)