I don’t think it’s accurate to call the barrier between a streamer and their audience “the fourth wall”. The fourth wall is a concept that exists in theater, and then more largely in fiction, where characters exist in a world where they do not know that they’re characters in a story. And the fourth wall breaks when they realize that they are.
If “chat” breaks the fourth wall, then self-help books that use “you” are too, or news anchors addressing their viewers, or politicians saying “my fellow countrymen” in a broadcast address.
It’s worth noting that in Italy, police communications are encrypted (they use TETRA radios, like most police forces in Europe). I’m not saying it can’t help prevent this, but when weighing the cost and benefits of encryption for police radios, we should take into account that this benefit is not absolute.