The GPL has nothing to do with usage and what others are doing with it. On the contrary: it explicitly provides the freedom to use the software as you wish, including for commercial use. Even Stallman is against licences that would prohibit commercial use.

But the GPL goes even further than that, and this appears to be the source of your confusion. The GPL stops people redistributing the software under terms that would restrict or prohibit use, including commercial use. The GPL guarantees that anyone receiving the software now or in the future has the same rights you have.