If they didn't and just pushed out they were being aggressive. If OP waved a few through then stopped doing that and just start moving forward exactly as she should do given that a) it was her right of way and b) she had a responsibility to the traffic behind her to keep it flowing on the main road she was not being aggressive at all.
You're wrong.
It makes no difference at all that the other cars were driving aggressively, or that they didn't actually have the right of way. The only pertinent fact was that they were the cars occupying the road. When other cars are occupying the road you cannot nose in.
There is no moral right involved with the concept of right of way or with any other driving regulation, anywhere. The entire exercise is a matter of using common sense along with the basic principle of driving defensively. Having the right of way doesn't eliminate the necessity for smart, safe driving. So yes, she had right of way, but no, she shouldn't have tried to exercise that right.
If one party to a traffic situation isn't driving safely or smartly, then the other one needs to. The smart, safe driver - aka the defensive driver - sees aggressive driving and doesn't try to nose in.
Smart, safe driving in this case involved staying put, letting the other cars off in front of her regardless of the fact that she had right of way and regardless of how many cars there were, letting the traffic behind the OP see for themselves that there was a procession, and letting those other drivers make their own decisions.
You do not have to take on responsibility for enforcing the rules of the road when you are driving. You do not have responsibility to the traffic behind you. You just mind your own business, driving defensively, and you let other drivers mind theirs.
This element of responsibility to the traffic behind you is actually ludicrous. Does it mean you can't jam on your brakes to avoid hitting a toddler who runs out in front of you because you believe you would be responsible for the actions of the driver behind you if you were to stop suddenly?
The reason why the fault in a crash lies with the driver who crashes into the other vehicle is so that nobody would be tempted to hit the child and keep on going in that scenario. Every individual driver is expected to make their own decisions based on traffic conditions and is obliged to stay alert enough to ensure their decisions are the safe, defensive decisions that driving demands.