Nope. a total douche-bag by all means. let's set aside the rudeness of what he/she did, this actually put the group in danger; so not only was it disrespectful, what he/she did was also dangerous. if that was my group, somebody would have pulled that douche bag aside or honked or yelled or all of the above. if you want to pass a large group, you wait for a good opportunity and you zoom past by them. you don't disarray a riding group putting peoples safety in jeopardy.