I think the article is using wrong examples if they talk about web companies such as Facebook, Google or Twitter. The GPL doesn't force you to free code you do

I think the article is using wrong examples if they talk about web companies such as Facebook, Google or Twitter. The GPL doesn't force you to free code you don't distribute, for example the code behind your server. This means that, if Facebook did use a GPLed library to, say, show you advertisemnts based on your 'likes', they wouldn't have to GPL their modifications (if any) or the part of proprietary software that used that specific library, let alone their whole infrastructure. So this argument simply doesn't apply to this kind of software. A license that forces you to release your modifications even if you don't distribute your software (again, a web application for example) is the Afero GPL, that is just another beast. TL;DR If you don't distribute or sell software, the GPL is not a concern.