I think it's an overreaching CYA - I doubt any of us really have to worry that Medium has DESIGNS on our STUFF, good or craptastic as it may be. But here's the thing - as a contract, it is horribly one-sided and not at all author-friendly, and WHAT, pray tell, is their PRODUCT - should they wish to sell or monetize Medium in any way? So no - screw this.