There isn't a reddit clone on ZeroNet yet.
>With zeronet the entire thing is synced.
Not really. Each zite is sandboxed, and within a zite, ZN tends to download files as you need them. This is useful since the cache folders have size limits. You can easily increase the limit if the zite needs more space.
There is something akin to if Reddit had a single subreddit (ZeroTalk). Of course, for anyone so inclined, it's possible to copy a zite's code/content and start a different community. This is something that's possible on ZeroNet that the traditional web does not really support (e.g. reddit has code that runs on its backend that users can't inspect, whereas with ZeroNet basically everything is client-side).