Even if they effectively delete /r/golang or close it while retaining control so others can't use it, the users will just create another one. I doubt it will have a large impact on the future of golang on Reddit, it will just get rid of years of discussion and make it slightly more difficult to use. You don't want to use Reddit? Cool, don't. There are still millions who do want to use it and some might use that to find information on golang.