Fedora tracks licenses on a package by package basis. You can fairly easily determine what the license of a library you use is, and recursively examine dependencies to see if there is something objectionable in there.
FreeBSD ships GPLv3 ports (gcc47, ...). So... it's not just smooth sailing there, either.
Linux itself is fine with the GPL. Thats an OS only.
The problem is usually the Linux dist. Their solution to the packages problem is to include the kitchen sink.
Licensing is along the lines of "what's that". Ergo you use FreeBSD (or one of the others) when you need to have something to satisfy lawyers.
It's all tracked.
Companies can modify some minor bit for their "secret sauce" and bundle it up inside the vacuum cleaner. Not the hacker version.
Since the internet of the future is the "internet of things" that's kinda important.