If you've ever checked new on askreddit, there were quite some questions like that on there too (and people usually answered them because... well why not I guess, everyone's just killing time on there anyway).
I think as long as there aren't many posts anyway, it doesn't really matter. Once there are, it's unlikely the not open ended questions would get much traction. Maybe /r/outoftheloop or /r/nostupidquestions style posts would also get upvoted, at which point it would probably make sense to seperate the concepts. For now that seems a bit needless imo.
Having multicommunities (either the option to automatically combine all communities with the same name across federated instances into one feed, or some sort of manual linking from the mod side where a community gets combined outward facing while still being hosted across servers with seperate mods) has already been brought up and would be a very good feature to mitigate this issue too. It's not something that has to stay impossible forever.