More like parties that are not technologically advanced nation states. Russia has its own satellites, China will find 10 ways around the problem, but a few random dudes won't be able to DIY a cruise missile with cheap parts that would be precise enough to be dangerous.

Or at least that's how I always understood it.

Actually civilian GPS would work fine in low-cost cruise missiles because they fly relatively low and slow. The restrictions are to protect against ballistic missiles.