Most Fediverse software supports image uploads, so there’s no reason to use Imgur for image hosting. Hell, even on my small single-user server (atomicpoet.org), image hosting is easy peasy. Not only is Imgur not needed, they’re an annoyance for those of us who are used to seeing images natively on the Fediverse.
I know habits are hard to break, but just remember: this isn’t Reddit 🙂
That and to prevent megaleeching by scraping. It’s easier and cheaper to purchase curated lists of IPs than it is to bootstrap a tool to ban them based upon bandwidth.