Former Strava user myself (well, I still use it to log my rides for my own record-keeping, but all data is private). I can't say it ever had any major effect on the social aspect of the local group rides, but one can very easily get wrapped up in riding the way you want others to see versus how you want to train/should train ... focusing too much on your distance, elevation, and mileage so others will give you digital high-fives. Cycling is far more enjoyable without it.

My favorites are the 177 bpm average, 19.9 mph "chill afternoon recovery ride" everyone posts on Strava. Gimme a break!