OK, there are two separate NEC codes at work here. Both came about under separate circumstances. One code was written to govern the grounding of antenna systems. If you remember, off-air antennas were first installed with 300-ohm flat wire. There was no way to ground that flat wire. In the event an overhead high voltage wire such as power lines or the power mains feeding the house somehow came into contact with that antenna, the ground should cause enough of a sudden current flow to cause a high enough current rise in the power system to trip whatever breaker/shunt was protecting that system.
In the case of a cable TV system, there was no on-premise antenna to be grounded. However, the potential for high voltage currents to come into contact with the cable system (it is below power on the pole) was still a reality. There needed to be a way to keep any high current coming down that cable to be dissipated to ground long enough to create a current rise that would trip whatever breaker/shunt was protecting the power source energizing the cabling. That method involved providing a path from the shielding of a cable to the house ground, aka, the ground block.
Grounding systems aren't really intended to carry current over a period of time. They facilitate a way of removing power from places that power would be dangerous to people and property. The way to do that is through extremely low resistance so that the current flow rises to a point high enough to trip a breaker.
Two separate systems, Off-air antenna and CATV, each with their own codes to protect those individual systems. Satellite dishes are the first real system that incorporates both systems. So, the reality is you should have at minimum, a ground block that is properly grounded to protect the introduction of harmful current into the home from the cabling. On new dishes, the dish itself is often isolated from the cabling by a plastic yoke, etc. In that case, the code should still technically stand. However, with the cabling ground in place, the dish ground is still technically unnecessary. That said, I would still suggest grounding the dish in those cases where overhead power lines are present such as a home that has overhead power service. Another circumstance would be if some idiot ran romex underneath his eave without installing it in conduit. I would even do it in those circumstances where you believe Christmas lights might be installed where they can come in contact with the dish. The code doesn't provide for all these potential circumstances. It just covers all the bases without any regard for the ability of the installer to determine the level of risk.
So, for the OP, if your cabling is grounded and your dish is not in a place where it is likely to suffer accidental contact with high voltage wires, I wouldn't really worry about it.
