are copyrighted unless otherwise noted and are the property of Cara and/or the individual artist
The hateboner is justified. For all it's faults, instagram explicitly says it doesn't own any of the pictures and only has a license to display which the user can revoke at anytime.
Deviant art has this in it's TOS:
DeviantArt does not claim ownership rights in your works or other materials posted by you to DeviantArt (Your Content).
It might be due to plain incompetence and not malice but their TOS lets them do a lot more than most platforms.