To be clear, I'm not saying that Instagram actually is any better than Meta/Facebook - but that their public perception isn't as disasterously tainted.
It's interesting. In media, Instagram is often portrayed as a device for young teens to feel insecure about themselves, leading to suicides and depressions, and the lack of any meaningful intervention by Meta/Instagram. Is that really a better public perception than privacy violations? Realistically looking at this, I doubt they'd get much of the Mastodon crowd, which is, grossly exaggerating, mostly tech and LGBTQ. So what remains is "normal" people who care about "normal" topics. I doubt these people care much about privacy (most of them are already on FB and Instagram).