I’d guess the simple answer may be that people don’t care/know, but for those that have ditched Facebook for whatever reason, yet still use Instagram, it’s a little surprising.
Is it partly a result of it being a more focused/limited form of social media that filters out some of the stuff people didn’t like from Facebook?
I feel like it’s 100% a “they don’t care,” the vast majority of social media users couldn’t give less of a shit who runs the service, just what the service does for them.
The average person didn’t quit Facebook because it was a gross invasion of privacy and FB was caught doing plenty of suspect shit - Facebook declined because it wasn’t “cool” anymore and that’s it. People on Lemmy are more likely to care about who’s behind the service, but the average user certainly isn’t going to care much or at all.