> "Thank you, now we can do anything we want to with it, including sell it,"
If this part (obviously this isn't the exact phrasing) was removed, then they wouldn't have the right to serve your content on their site. They couldn't use a screenshot containing your content in any advertising they did. They couldn't use your content alongside advertising. They couldn't do a lot of things they do now.
Allowing someone to upload something doesn't inherently give you any rights to use that content. If you remove the parts you are complaining about, then they can't do anything that they are doing.
If this part (obviously this isn't the exact phrasing) was removed, then they wouldn't have the right to serve your content on their site. They couldn't use a screenshot containing your content in any advertising they did. They couldn't use your content alongside advertising. They couldn't do a lot of things they do now.
Allowing someone to upload something doesn't inherently give you any rights to use that content. If you remove the parts you are complaining about, then they can't do anything that they are doing.