This article gives a clear and easy understanding: http://www.europarl.europa.eu/news/en/press-room/20180906IPR12103/parliament-ado...
News media are worry that big companies will just remove everything to keep things safe but that is not how that law works. Also no it will not kill itch.io it is as of now still a start-up which is safe from the EU law. the only companies that will get damage in the game development is Steam/Valve, Facebook Gaming Room, Gamefly and Humble Bundle because they are the big ones, everyone else like Gamejolt, Green Man, GG and indiexpo are not going to be targeted until they become big.