In other words, NBC is trying to cordon off access to video streaming of the Olympics unless you're paying for a cable TV package that includes NBC channels (even though this is all free over the air with an antenna). ... NBC could have simply offered the Olympics streamed with ads to anyone interested in watching, given it's already broadcast free over the air.
Umm... You realize this is all wrong, right?
NBCU runs MSNBC, USA, CNBC, etc. Those channels are showing more Olympics coverage than the OTA NBC channel. So the theory that "all this is available for free over the air" is simply wrong.
Most NBC content is subscription based. Only the one channel is free. That's the reason for the subscription requirement.