The GPL carves out exceptions for the use of system libraries.
But, as for the "dangerous" part:
* I work in an industry in which software patents are required to survive. Personally, I hate software patents, but it is a reality until the law changes. As such, the GPL invalidates patents, making anything GPL completely off limits. That means that I would not have a job, and then there would be fewer competitors in the marketplace, which would make prices rise considerably. Too bad, too, because we would donate back improvements that are general enough to benefit others. Rather, now we just use proprietary solutions wholly because GPL is a minefield for us.
* I have personal projects. I write code that I want to use myself as well as allow others to use. I use MIT because GPL discourages that somewhat (the point above). I may want to use my personal projects commercially some day. MIT allows that; GPL makes it impossible. In other words, if I choose GPL today, I have poisoned that code from myself for the rest of my life.
In short GPL is not "free" as in freedom, because it comes with strings attached. It's communist in philosophy, but I hesitate to say that because then everybody jumps to some *a priori* conclusion of what they are now convinced that I'm saying, without listening to what I'm actually saying.
GPL says, in short, that the software is freely available for public use, but not for private use. (Yes, there are nuances to that, so much so (and so confusing) that most people either just ignore it, or say "IANAL...") It demands that 100% of the work of anyone in the future must be donated back to the collective for free. That is not freedom.
Create as much GPL code as you like. I create MIT. You can use mine (and I'm happy for you to!), but I can't use yours because of the restrictions you put on it. We can let the future decide which is more "free".