Downvotes are almost never used correctly. People think if something isn't for them, it deserves a downvote. An inevitable bit of Reddit culture that comes with that user base jumping ship. Nonetheless, it could only cause the death of a community if the people in that community don't choose to spend time there.

When I browse my subscriptions, it doesn't matter if the posts I want to see score too low on the vote scale to be discoverable in All. I'm going to see them, because they're what I came to see. I went looking for those communities, and curated my own feed. I think if more people went looking for stuff they want to see instead of letting their client show them whatever is doing well on votes, the votes wouldn't matter nearly as much.