Okay, so this is really only accurate if your bot is running in a single channel. Per that same thread, a Twitch staffer responds by stating that if a bot is modded in all channels it is in, it can send 100 messages per 30 seconds across all channels, so if that bot is in 100 channels, that means 1 message per channel per 30 seconds.
From the looks of it, multi-channel bots solve this with multiple connections. That is a bit mind boggling, but perhaps there is a reason behind it that I’m missing.