The term "open source" is well defined by OSS. It seems like the client itself is open source, but the server is under a proprietary license. So yeah, this aint it.
I hope you dont give up on it for too long, I think it's a great OS once you get the hang of nix. To this day, its the only OS I trust where I could install anything I want and can still rollback without worries. Also I can make sure that my installation is the same as others, which means other people can literally just copy paste my config to test.
What's the actual wording here, access to internet, or access to certain websites?