The streamers attracted many gamblers to follow them by joining them using their referrals. The bonuses received by the streamers also became large, making them promote their casino more often. And when those streamers get big with lots of followers, they might find it easier to attract gamblers who have just watched their videos because there are already lots of people joining using their referrals.
And this is why the people who join the streamer must be able to control themselves because the streamer promotes the casino, while those people join because they are interested in gambling. And if they can't control themselves, they will only lose a lot, making them sad and regret it.
Also streamers and other influencers are selling a false image of what gambling is about as they share their wins but they do not tell their audience that they were not risking their own money, and instead that money was given to them by the casino they are promoting, so they are literally gambling with free money, while anyone that watches those streams and tries to imitate them will find out they cannot get the same results as they are risking their limited capital instead.