I've never ridden anything longer than a 200km event. I have limited time, and can't always keep fit enough even for that. I wish there were more shorter events. I'd like to try a 300km event sometime, but if I'm honest I probably have no wish to ride for 24 hours.
However, I have to respect the fact that Audax is a long-distance cycling association and, when used in that context, "long" means "including well over 1000km in one event". Thus, the events I ride are further than quite a few people, even in my cycling club, have ever ridden, but are "short" in Audax terms. From the perspective of many Audaxers, they are taster or starter events, or training for the real stuff.
If I join something where I don't choose to take the greatest challenges, I'm not sure that I would see those who do make that choice as "elitist", any more than, if I joined a golf club, I would see those who worked hard at getting their handicaps down, or actually took advantage of a trainer, as meeting that description. Nor would I think that, by merely talking about what they were doing, they were attacking my lesser participation.
I suppose those who want a medium-distance association could start one, but I'd rather listen in awe to tales of massive mileages, and carry on enjoying 100s such as the one I rode yesterday, where everyone, even those who can ride, and have ridden, much further, was very friendly.