I think that the big confusion comes from people confusing the GPL with LGPL.

LGPL was designed to allow other products to incorporate the project without having to GPL the entire product. Many open source libraries are LGPL.

GPL requires that any product that utilizes the GPL code (not interacts with it like a browser with a web server, but utilizes the code to facilitate function) fall under GPL license or a even less restrictive one.

Additionally, people do not realize that you can charge for GPL code as mentioned above.

JMass