They might be referring to *GPL libraries not allowing proprietary / permissive exes to static-link them. e.g. I think Qt requires its DLLs to be separate on disk as part of the LGPL, unless you buy the commercial license.

Please don’t spread misinformation, there’s a HUGE difference between GPL and LGPL, and you CAN statically link with LGPL you just must provide the object files to the user so they can re-link them with any version of Qt they want.