That function appears in hundreds, if not thousands of GitHub repos. It's plausible that it's the most famous block of code ever. Are all those repos guilty of copyright infringement?

https://github.com/search?q=float+Q_rsqrt%28+float+number+%2...

The only ways this argument could be less alarming to me is if people were bothered that it was writing the same Hello World as somebody else, or that it was naming variables "foo" and "bar".

Let's wait until we have a bulletproof, egregious, and inexcusable case of it lifting code until we panic.