It's good that they do have restrictions but I think it's much better if they filtered out real and fake gambling sites, but I think it's really hard work to spot which sites are fake or not since some legitimate gambling sites can turn into scam and there's no way we can predict or to know that.
that might be the problem. they don't filter which ones are legit or not. but generalizes everything. Their idea of protecting their users from fake casinos and online scams is very good. but there must be a way other than completely banning streamers from sharing their ref links. but it seems that very few gambling streamers have complained about this policy, they can still exist on Twitch and get other benefits from streaming.