At least for two of the websites listed by Twitch in the new policy, the websites themselves don’t set the odds. They don’t even make the slot games. A third party creates the games, sets the odds, and provides these websites an API for them to use.
Two of those websites, the ones I’m familiar with, use (at least some of) the same third party websites. For example, Pragmatic Play.
It’s a vastly different conspiracy to say that the websites listed on Twitch’s policy are setting odds in favor of their affiliates when it involves at least two different companies.
That’s not to say this has never happened before, though. There was previously a website called CSGO Shuffle on Twitch that was setting odds in favor of their owners and partners, but those owners and partners also didn’t disclose that they were advertising and didn’t disclose that they were involved in the company.
https://www.theverge.com/2016/7/21/12246138/twitch-bans-phan...