There is definitely a large amount of narcissism present in a gym environment and the “fit lifestyle,” as you put it. Yes, people post selfies and admire themselves, but if that’s the motivation they use to keep them from being fat and lazy, then more power to them. Is it really harming you? More than one third of adults in the US are obese, and that number is rising. It seems like maybe more people need to love themselves and do something about their health.
I get you were just ranting, but turn that anger into motivation! Keep at the pull ups. You will see progress in time, and you will feel better for it. It’s not a bad thing to be concerned with your looks or progress, just be realistic and don’t let your narcissism harm others.