Since hobby joggers are generally not fast, I believe they will therefore "compete" on what they are best at.
Example - slow hobby joggers who can churn out lots of 4 hour marathons will brag that they run 10 marathons per year.
Example - attention seeking hobby joggers who grow a beard, get tattoos, and wear compression socks with skulls and churn out a 50k ultra, or a 3:25 marathon, and receives great adulation from his running club.
Example - a non runner who does a Color Run and posts it on Instagram to show off.
The three guys above won't even enter a 10k because running a 44 minute 10k is not something they can brag about. So when they see an actual real running crushing it out there, they feel uncomfortable and insecure and yell something out to try to diminish what you are doing.
My advice - ALWAYS do your best. Your actions, and nobody else's, are what reflect on your character as a person. They are the ones that need to change, not you.