It's the very act of distribution that contains the problem. If you use a GPL'd work in another work, your distribution of the other work must be GPL'd as well. GPL'd part + non-GPL'd-but-compatible part = GPL'd whole, but the parts still exist on their own under their respective original licenses.

See Tomte's sibling comment to yours (https://news.ycombinator.com/item?id=39840391) and my own other comment (https://news.ycombinator.com/item?id=39841923).