When a machine moderates content, it evaluates text and images as data using an algorithm that has been trained on existing data sets. The process for selecting training data has come under fire as it’s been shown to have racial, gender and other biases.
Unfortunately those are not platforms meant for archiving, it’s in their own TOS they can take down any content or entire accounts at their own will and for undisclosed reasons. Also those platforms are subject to shitty practices like report abusing, yet another reason to put your content in danger.
Also unfortunately they are very attractive because of the influence a person can build with large network of followers in those platforms and how they can leverage that.
I don’t see a plausible solution or alternative. Instagram, Facebook, are the platform of the masses and where your content has the highest exposure. People today aren’t browsing “the web” like we used to back then. Instagram/Facebook are the internet.