First things first: What is Slothicorn?
The Slothicorn project is one of the very first project on Steem that focuses on curating art related contents (from drawing, painting, animation even to comics and food arts).
Here's @stellabelle's reason (founder of the Slothicorn project and was at some point it's largest delegator) as to why she decided to step out of the Slothicorn project:
Image Source: https://steemit.com/partiko/@stellabelle/banana-program-new-steem-project-designed-for-bored-humans
It seems her main reason was the project was purely running on "charity" and she wasn't earning any ROI which is quite understandable with the market crashing. With her delegation gone, the project can't just stand on itself. :)