The unfortunate reality is that all these big companies work like that now; they don't want to pay people to moderate manually, so they have all that be run by automated processes that work more to sweep away people the algorithm thinks are likely to be a problem somehow rather than enforcing specific rules. At various times I've heard of content on Instagram I might be interested in, but they don't make it accessible without an account, I'm not willing to make an account or install the app and it sounds like they actively prevent access to third party software so I just gave up.
Maybe it's possible your ban had to do with your pattern of use of the platform; like if you were messaging a bunch of people asking for permission to share their photos, the algorithm may have taken issue with the similarity, spread and frequency of your requests without considering their content or purpose. Ultimately though who knows. Reminds me of when I was banned from Facebook, of course they aren't saying why and of course they aren't giving any coherent response, you can only guess.