Just my two cents thinking off the beaten path like always in life leading revolutions...
Without me dedicating time valuable time to reading through those arduous terms and conditions line by line, SS likely has some caveat in there much like Google and every other aristocratic organization in Silicon Valley that allows them to use your uploaded images and content for some acceptable purposes if need be.
The more content they have, the more valuable their database is as a company and their intellectual property.
They don't want you deleting that awesome content you've created and uploaded that they may be able to use for their marketing, advertising, or other purposes.
