Sure, but I would say that there's a reasonability test there. Like, I could have a posted note somewhere on the internet that says, "by allowing my computer to download your content you grant me full license to use your intellectual property for any purpose in perpetuity throughout the universe," but that doesn't make it binding on anyone. Federation means other servers pull the data, so you don't have control over it, so you can't be considered to agree to a random server's terms.
The same thing happens when you download a website. The website always allows others to download its content, but that confers no license no matter what anyone else says.
"License free" doesn't mean "free license", it means the opposite. No explicit permission is granted.