I'm skeptical of this kind of analysis without concrete examples of the kind of content that wasn't removed. Even if you trust the researchers (I personally am not familiar with them), there are legitimate reasons why they might not categorize things the same way as social media platforms. e: Turns out that the researchers' full report actually does contain concrete examples, which seem to be legitimately bad and tak…
I've reported this page countless times that purports to be about 'jewish contributions to society' but is clear as day dog whistling. https://www.instagram.com/jewish.contributions/?hl=en
I think it is dog whistling, but if you aren't familiar with anti-Semitic arguments and angles of attack, I don't think it is clear at all, which is probably the point.
On the surface it just seems like a list of facts and some are even seemingly laudatory, such as helping to end apartheid. The bad stuff is subtle or lower down the page.
If I were a moderator and just doing a quick check, I probably wouldn't spot anything wrong with the page.