Paul
Perhaps those "ignorant" people who got in your way had not been told that the rally had been put on just for groups of photographers
I am afraid that's life and "if you let it", can be very frustrating and annoying to the point it spoils your enjoyment of the day.
Sometimes its best to take a chill pill and walk away and come back later when the crowds have gone. Just remember they have exactly the same rights to stand there that you have.
Phil