They were following Twitch’s instructions and going along with their votes. Calm down.
Only, they didn't: Categorically, Twitch was given a formal, pre-planned deliberate choice, they made that choice, and then the streamers discarded it and did something completely different anyway.
Outside of that, Swen's behaviour and commentary was not, at all 'a harmless, silly bit of marketing'. His presentation and behaviour was not okay.