I would go a step further and say the first thing a new Reddit account should do is unsubscribe from everything, then selectively subscribe to your interests. Every default subreddit is horrible.
In my experience, the academic subreddits found in the defaults are pretty civil (i.e. science, philosophy, space, history). But they all have well-defined mission statements and heavy-handed moderation (e.g. no memes or any other kind of offtopic discussion).
That said, starting from zero is still a good idea.
