It not only ignores them but people purposely place these restrictions on them for greedy reasons.

Frankly, in my experience it doesn't take a lot to enable multicast and doing it internet wide _shouldn't_ be that big of a deal so we can handle all the streaming of live events with little worry - but the "powers that be" want to restrict everything online and it's frustrating, angering and downright dangerous attitude to have as a defacto "standard".