The license is with regards to “GOG Service”, not “GOG Contents”. You need the former to get access to the latter, sure. But what isn’t clear about this?
You still own the contents (though, as mentioned, individual titles may have additional blablabla). If you don’t think this distinction makes sense when it comes to GoG vs Steam, then maybe you’re just discussing something entirely different?
The license is with regards to “GOG Service”, not “GOG Contents”. You need the former to get access to the latter, sure. But what isn’t clear about this?
You still own the contents (though, as mentioned, individual titles may have additional blablabla). If you don’t think this distinction makes sense when it comes to GoG vs Steam, then maybe you’re just discussing something entirely different?