What I find extraordinary is that this is not the “dark web” or even a regular porn site. Instagram is used by millions, belongs now, I believe, to Facebook. Facebook is surely culpable in not removing these users from their sites. They use bots all the time to monitor what we post and what we interact with in order to send us advertisements. They can just as easily spot the would be abusers and take the appropriate action. It should not be left to people like you.