How many Streamers or Influencers do you know who were banned due to collusion with the casino? For YouTube to ban an account you need hard evidence that you can't provide. So the only really workable way to influence this kind of activity is to reduce the number of subscribers in all of the streamer's social networks.
Which does not really make a lot of sense, after all if a company tried to scam me then I will never use their products and services and the same is true for anyone that was advertising them, but when it comes to streamers people give them most of the time the benefit of the doubt.
Nowadays, the competition on the market is very high, so it is easy to find a replacement for your favorite streamer. By continuing to watch his content you support his activities.