I'd say it's more convenience than elitism.
I'm in BTN and it's the only indexer I use for my Sonarr instance because it has absolutely everything. I've never not been able to find something and almost everything I download will saturate my 1.2 Gbps connection.
For Radarr I don't have any private trackers and it takes 35 public trackers to get coverage that is almost as good. The options I'm given are way less organized and download speeds are a gamble. It's not really an issue because I rarely watch movies, but I definitely understand why private trackers are so sought after. I'll eventually try to get into some smaller ones which tend to be pretty easy to do.