Is this dataset now copyrighted?

The provided URLs don't give direct access to the images. The real URLs are of the form

https://images.dpchallenge.com/images_challenge/1000-1999/1396/1200/Copyrighted_Image_Reuse_Prohibited_953417.jpg

which spells out "Copyrighted_Image_Reuse_Prohibited".

Can the author of the repo confirm that the use of the dataset is not allowed anymore by DPChallenge making this repo useless?