Who's talking server side code? just releasing the compiled server binary should be enough. Just like games typically are released as binaries and assets, and not as source code.

Can you decompile the server binary? Yes you can! But you can also decompile the game to work without the server or with a makeshift server. Either is just a lot of work that few people are willing to do.

Protecting the server code is rather useless if the game can be cracked, since then you can also play the game for '0.00 €$'.

I mean this isn’t about asking the companies nicely to do this. We are asking law makers to enforce this by law. We are past asking corporations to not be crap.