My impression of the IAC then was a narrow-minded, opinionated "good old boy" organization with very subjective judging and matching attitudes. Recently one of my F16 bros reported a similar reception at a nearby event in his RV4.
That kind of attitude is one of my bigger concerns, actually. At the two contests I've been to (as a spectator or volunteer), most folks who saw my RV parked on the ramp and asked about it seemed pretty cool. There was one Pitts guy who was pretty snobbish and seemed to have a genuine dislike for RVs but I attributed that to the individual and not IAC in general.
I would caution anyone against holding reservations such as this before gathering sufficient personal experience. There are a million ways to overthink and overanalyze the decision to jump in and whether you are ready to get involved. It really comes down to that - jumping in. It's a club you admit yourself into. Requires somewhat of a self-starter attitude and maybe a bit of confidence. For 99% percent of 1st time competitors who have them, the reservations evaporate that first time out.
Regarding the impression of IAC being a bunch of "narrow-minded, opinionated good old boys", you will find a small percentage of jerks no matter what type of activity you're into. That's life. It may not come as news to many here that RV pilots aren't exactly positively viewed by many in the rest of the GA community. Do I think RVers are any different overall? Nope.
The judging does seem to be extremely subjective. At the contest in Spencer IA where I did recording both days, I saw that a number of flights had wildly different scores from the different judges.
Anyone interested in this sport would greatly benefit from attending a judges school to understand the judging criteria. It can be quite complex, but it is NOT subjective at all. Judging can vary a bit because humans are involved, but in general, the judging process selects the overall standings quite fairly.
I have attended about 20 contests in the past 9 years up and down the east coast, and at no contest did I feel the overall standings were not correctly determined, even if there may have been certain single figure scores from individual judges that I disagreed with. In the end, the system works very well. In my experience, the pilot who wins is the pilot who either flies the best or makes the fewest technical mistakes. Become a judge. Gain experience. Educate others if you feel it necessary.
Nothing is hidden. Anyone can look up the scores IAC judges award here:
http://iaccdb.org Same for world level competition:
http://civa-results.com Yes, some variation exists anywhere you go, but overall your scores really do accurately reflect the level of effort, practice, and critiquing you have invested in your flying.
Regarding "snobbish" attitude toward RVs, I haven't seen that. What I have seen at contests is a very diverse field of aircraft types including Stearmans, Clipped Cubs, T-Crafts, Robins, Chipmunks, Jungmanns, CJ-6, T-28, Sonex, C-152 Aerobat, Citabrias, and even a P-51. Not exactly traditional competition acro planes. The RV is not special. It's just another capable aerobatic airplane.