Author here :) Endgame exploits/abuses features. If it was a bug, I'd work with AWS to solve the problem, but with abusing features - that would result in years of unsatisfied feature requests. This should push the issue along.
>...and it's not even a hacking tool! It can be used to backdoor resources to rogue accounts, so I'd say it's a hacking tool and can/should be used on penetration tests. I'd certainly use it on a pentest :)