@mjgardner Reddit isn't like other social networks, it relies on it's unpaid volunteer moderators (of which there are thousands) to keep content safe, relevant, and legal. Since moderators control the subreddits they moderate, they are also participating in the protest.

So reddit could forcibly bring subreddits public again, but without the thousands of moderators, that's likely to end poorly. Even if you ignore the flagrant abuse that would occur, the subreddits still would lose much of the community that makes them interesting places. In many ways subreddits are made by their community moderation.