"birds of a feather flock together". It's not elitism, it's commonality. All humans are like that, it's a natural instinct. Some are more friendly than others, some take a longer time to warm up. Some never will. What the OP described is very similar to my experience, except I never took it personally:

Five years ago I showed up out at a local 'fast' ride on a hybrid with toe clips and me about 25 pounds overweight and with little to no experience riding in a paceline or other bike handling skills. This, like the ride you described, splits up into an A, B, C, groups and stragglers, unofficially, as people drop off from the fastest group. That fast, and definitely elite (both skills and attitude), group also rode a separate route on one night a week, further and as hard as any ride around.

I couldn't keep up with the slowest riders. The ride leader waited for me on the route a couple times until I knew it, then even he would leave me to finish the ride. Only a couple people talked to me.

I started riding one of the ride leaders bikes for a couple weeks to test it out. I could keep up with him and a couple of the slower riders. They coached me a little bit on riding in a paceline. A couple more people talked to me.

I bought the used bike and kept coming out. I could keep up with slightly faster riders over time, and gradually learned my skills. I also slowly got to know the riders. Eventually, the fastest A guys started to warm up to me. And eventually, as I proved myself strong enough and skilled enough, I started getting the question: "Well, are you comin' with us or not?" Even then I waited a couple more months before I attempted that ride.

I've been trying to keep up with those guys for the last 5 years. Some days I make it, most days I don't. But I never gave up. Those same guys who didn't even notice me when I first showed up, are now some of the best friends I've ever had.

Keep showing up, get stronger, give them time. Many guys don't bother because they assume you won't be back more than a couple times. And yes... get a more suitable bike, or alter your bike, if it is necessary to ride stronger and faster, and if that's what you want. You don't have to buy a super light $5000 carbon techno wonder. If you can keep up on that bike they'll actually be more impressed.