That's called a ban, not a shadowban.
There are two separate issues here:
- A bot that automatically removes users' posts and comments without actually banning them or telling them the items are being removed (this is a subreddit-specific "shadowban", though it's not a built-in feature of reddit it has the same effect)
- Moderators that eagerly attempt to ban all dissent, not only from their subreddit but from all of reddit
They are both wrong, both unforgivable, and both forms of censorship. Just ban people you don't like from your subreddit, no need to code custom bot features or try to lie to the reddit admins to accomplish political goals.
The mods of r/Bitcoin have also personally tried to get me banned from reddit through untrue accusations to the reddit admins (they tried to get me globally banned for "doxing" theymos, notice the timestamps: http://i.imgur.com/THhruNm.png when I called him by his first name, which he himself publicizes on his LinkedIn page as associated with his handle "theymos"). Obviously the ban had no merit so it did not stand up to admin scrutiny.