But this “gaping hole” is essentially true of almost all content posted on the internet and later deleted by the OP. Another user could have downloaded/copied it. The downloading process is made more efficient by the availability of an API, but is not exclusive to it.
So this “gaping hole” is really a feature of data on the internet in general - I don’t think it really says anything specific to iNaturalist that should strongly influence the discussion about this topic. People in general shouldn’t post anything online that they want to be sure isn’t accessible by others.
Despite this feature of the internet, almost all sites I know of allow users control over deleting their profile and most/all of their content. I looked into what other social networks allow for in terms of deletion. Here’s a summary for Twitter and Facebook based on the info I could find:
Twitter allows you to delete all of your content with a 30 day waiting period. You must deactivate your account for 30 days and not log in. If you log in during those 30 days, you can reactivate. However, if not, after 30 days all your content (tweets, pics, likes, everything) is deleted.
Facebook allows deactivation but also immediate deletion. Deactivation involves your profile disappearing, and most of your content becoming invisible to other users, but the account can be reactivated. Deletion involves deleting your profile and all content that you posted. It doesn’t however delete comments on other people’s content apparently and maybe some other things (this is a little fuzzy). Facebook explicitly gives a reminder that other people might have downloaded your content when you delete your account. There is also a 30 day grace period during which Facebook can recover your account after deletion.