They are right that Free software is important, not only games but other stuff as well; I agree with the ideas they mention in this article.

Freedom 1 is also important for understanding the rules of the game in case it is not documented very well; changing which server it connects to is not the only issue (and a well-designed FOSS program would have an option to configure which server it connects to without needing to recompile it).

(In some cases, other people figure out the rules of the game independently and might write independent FOSS implementations (in one case, I have done this for a single-player game; other people have also done for other games). In this case, it may be less of a problem (if the FOSS implementation is actually correct and complete (and might even have less bugs than the original and/or other improvements)), and both official and unofficial implementations can continue to be used.)