I believe the point of calling GPL code dangerous is that developers mistakenly believe that it is freely copiable, since it almost is. There's little danger of that misbelief with source code that one got from a former employer's internal code library.
I don't know if it's true that developers are misled by GPL in that way, but I've heard stories. When FSF describes GPL, it usually stresses that the code is is copyrighted, and is not public domain, which leads me to believe they've encountered such confusion.
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