He’s specifically referring to Reddit’s content moderation which actually has two levels of bans. Bans by mods from a specific subreddit are done by mods from that specific subreddit and having an explanation isn’t required but is sometimes given - these bans apply to just the subreddit and are more akin to a block by the community. Bans by admins happen to people that have been breaking a site rule, not a subreddit rule.

Both types of bans have privacy issues that result in lack of transparency with bans.