Your A.D. obviously doesn't like you and doesn't understand the nature of track and field. If he/she is on the older side you might be able to put up with the crap that will be dished out. If not, go elsewhere. It's too difficult to work with an idiot.
The wonderful thing about our sport is that kids get a chance to participate. I used to joke with my kids that j.v. runners even get in more "playing time" than varsity ones. Also that when the seven Kenyans move in our present varsity will become j.v. runners.
About parents complaining. I never had that problem. Since everything is timed and measured all kids get their chance. Track parents are happy that their kids are running around rather than sitting on a bench, although some kids would like to sit on the bench.
However, certain invitationals are strictly for varsity competitors. If you cannot communicate that to your A.D. you must give up and move on.