I am sure some of it is spam bots. But also - a big value of Reddit is indeed in the long tail of niche communities. Many did not join the protest.

Bots mostly. Take a look at the site, you'll notice many usernames consisting of a random adjective or noun in front of a random noun and a random number at the back. Sometimes they are in camel case, sometimes they are separated by dashes or underscores.

Go to the profiles of those. Bot accounts display that they are 6-12 months old and have no activity for the first few months. The activity starts with out-of-place comments on reposts made by other users (they never comment on OC), so they are likely copied from other users that commented below the original post.

After the initial commenting phase, they start posting. It's never OC, just reposts and they never reply to questions in the comments.

At this point I'm convinced those bots are deployed by reddit themselves because they are so easy to spot and no action is taken against them.

Then there's also the porn bots which collect properly tagged material from other sites and post it to the corresponding subreddits. You can spot them by looking at their profiles, they post 20-30 images an hour without pause. I'm pretty sure those are made by users, we'll see once the API changes go live.

Edit: Typos

A lot of people simply don't give a shit. Look at the amount of people still on Facebook.