No, presumption of innocence is first and foremost a moral principle. Our legal systems are reflections of our collective morals.
The extreme social media dynamics somehow holds these corporations accountable for any wrongdoings someone might post on their platforms which is impossible to prevent or moderate in a timely fashion. They respond with more sophisticated and sweeping algorithms that lead to self-censorship by content creators and unexpected actions like shutting down the demoscene event a few days ago.
Further, Twitch is not the entire industry, the same way that Microsoft is not the industry.
The suggestion that it is immoral for a different standard being applied to a private clubhouse is not something that was supported by the influential thinkers who gave us the former idea.
Twitch is hardly in that category, though.