They do not grasp a concept of a race, complete with official rules, referees, and people that are actually there to race. In their head a tri is a stunt weekend thing like a mud runner or a walk for cancer, and it is done for fun. No different when they go out to their local MUP to walk a dog. So when someone yells at them to stay right or stop blocking, of course from that worldview they will think they are being mistreated.