What do you mean by specs then? The protocol? The “protocol” is the ABI of the server binary, the logic of it. The networking protocol is super simple. You need the server code for replicating any server.
This is not enough, the code is old with vulnerabilities that will be exploited with automation nowadays. To correctly do this you need open source server code, or to have it maintained.
You dont seem to know what you are talking about, or are dissingenous.
Copyright is the tool that allows to enforce GPL. The same with other free and open source licenses.
You seem to be leaning towards “permissive” libertarian licenses like MIT and BSD. Those don’t care much about the end users (I got your code, now fuck off I can do whatever I want with the modifications, including never sharing them back and making the whole thing closed source).
But for GPL and licenses that protect the rights of developers (including the right to ask follow-up developers to keep the code open for the benefit of users and developers), copyright laws are the tool that enforces that.
Because it is copyright laundering, which is ilegal. We are just too early in the tech to have it established. But see cases open against Microsoft’s Copilot.