http://jptvwdeyknkv6oiwjtr2kxzehfnmcujl7rf7vytaikmwlvze773uiyyd.onion?page=7858549019864373005596
Many of the indexes out there are written as a little side hobby project.
They sometimes use crawlers to find additional links and to check if onion
services are still online periodically.
I don't necessarily think there's much harm in these side projects.