That's... somewhat true. My main objection is to "the author is the only one holding every rights on the code and every use that is not explicitly allowed is a

That's... somewhat true. My main objection is to "the author is the only one holding every rights on the code and every use that is not explicitly allowed is a copyright infringement (unless it's fair use)". The ToS doesn't say there's an implicit reproduction license, though; it says there's an explicit reproduction license. The other licenses can still be argued to be implicit. For instance, you have a decent argument that local clones are an implicit license – GitHub provides a "Clone or download" button directly on the repo page, and it's one of the main use cases of GitHub. (Other arguments exist.)