If someone pulls from a side road into your path on a major road, because they are in a procession and you didn't let them out, they have caused the accident.
You are wrong there. If an accident were to occur in that instance, the first question the insurance company would ask is, 'Did you brake?' They would want to know why you kept going despite seeing that the cars were processing ahead of you, regardless of who had the right of way.
The OP was yielding the right of way to the procession though. So this wasn't a case of cars 'in her path'.
If you are stopped while you let a procession go ahead and then decide to cut in based not on the fact that there seems to be an opening in the traffic but only on your view of what is a proper number of mourners at a funeral and what they should be wearing, then you are responsible for whatever accident follows. You can see them all processing and regardless of whether there are five or five hundred mourners, the fact that they are in motion and you are stationary means you have to stay put until there is enough of a gap in the traffic to let you in.
Your feelings of anxiety about two hundred people taking the piss or about being late, or the fact that you have the right of way are all irrelevant. You do not teach other people the rules of the road using your moving car as a teaching prop.
Driving aggressively in response to the aggressive or illegal or inappropriate driving of someone else, or because you are putting 'rights' before common sense, is never the good option.
Two aggressive drivers is a recipe for problems. You should always drive defensively. Let the other guy take the risks of driving aggressively if that is what he wants.