It is basically a fact that even if the activity you are promoting has a significant downside or risk but when you tell all your audience about the dangers and adverse effects that the activity can cause then ultimately it is less likely for people to blame you when they experience the adverse effects of the activity, because from the beginning you have told them about the downside of gambling if done in the wrong way, but from most of the promotions of gambling sites that are promoted especially on some social media usually stremers really only show everything that looks tempting.
Yeah, but I think the audience should be mature enough to understand the downsides of gambling even if a streamer doesn't say it specifically because you can't expect to win all the time in gambling, however, as you said, streamers tend to show the positive sides most of the times because it's their job or responsibility to promote the platforms they are gambling on because they have partnerships with them and they get paid for doing that.
So when a streamer gives a warning on their streams or even write it somewhere in the description or the screen that gambling can have adverse effects on people and their minds because it can cause extreme losses if not done carefully, so everyone should gamble at their own risk and they aren't responsible for any losses occurred.