I think you are confusing something. A tech company running proprietary code can and will ask for age verification. It does not matter if the user runs Windows, Linux, iOS, GrapheneOS.

The law here makes sure that services, which are basically also open source, are not required to do the age verification check.

So, you install Windows? Age check. You install Linux? No age check. Before even opening a browser. Then on Linux you open Netflix? Age check.

So I fundamentally saw this actually as a good news.