You're not forced to use anything. The problem is that many projects choose licenses without carefully assessing all the trade-offs. If someone already built t

You're not forced to use anything. The problem is that many projects choose licenses without carefully assessing all the trade-offs. If someone already built the thing you need but chose to release it under the GPL it might as well not exist if you can't use GPL code in your project. This is especially true if the value added by the library is minute in comparison to the overall scope of the project (this is by design). Just ask any developer who inherited a non-GPL project from a junior developer who doesn't understand licenses and accidentally used GNU readline. If a library naively omits the license altogether (based on a widespread misunderstanding that "no license" means "public domain"), they will usually be able to switch to an open source license easily. If a library naively uses a permissive license, you can simply incorporate them in your project (whether that project is GPL or not). If a library naively uses the GPL, not only are they likely locked into it until the end of time but the code might as well not have been written at all unless your project is already GPL or you are willing and able to switch your license to GPL.