Re: So what did YOU do then ?
GPL3 requires nothing to be released to the public domain at all. Quite the opposite. Release in this way would be violation. It does have requires about release under GPL3.
Nor is "anything it touches" correct. You can use GPL3 (or 2 or 1) to create, manipulate other code. You can use it to perform any kind of analysis you want. You can launch GPL3 code, or use GPL3 code to launch other code. None of this requires any release under GPL3.
You can even modify GPL3 code, and do almost anything you want with that code. The only thing that you cannot do is distribute the modification without also releasing it under GPL3.
Of course, this is a limitation and will prevent people from using the software under some circumstances. It is designed to do this. It's useful and reasonable, depending on your motivations for writing free software. In some cases, there have even been strong commercial motivations for using GPL3.
It's quite a long way away from "metastasis and infect" (two different things by the way). It may be a stronger quid pro quo than you want under all circumstances, but it is right for many.
Biting the hand that feeds IT
