Hi coin-investor,
Thank you for pointing that out. I apologize for any confusion caused. The correct information about the promotion can be found here
https://filesity.com/promotion.
You can post any kind of file as long as it’s not a virus or illegal content. This includes free e-books, music, videos, and more.
I recommend that you edit your thread and include the link you provided because there's conflict and confusion because your how it works on your post is very much different from the how it works on the platform you're promoting.
And besides not all free items you can find online are free and legal for distribution because there's attach terms on this free items that you cannot monetize or you should ask first the author or publishers for distribution.