Is it allowed in the livestream, e.g. Drink alcohol or beer on twitch or Youtube?
On Twitch, you definitely have to make the stream starting at 18, and maybe stop drinking until it crashes.
What should be forbidden?
Yes, some of the minors are looking for it and find it cool and then they want to imitate it
Well and? It is up to the Setenbetreibers to provide for youth protection. In addition, there are enough other possibilities in the net to look at what is not suitable for the elderly. The kids these days are not stupid.