You mean the Justice League run that makes the Silmarillion feel like Dr. Seuss when it comes to overly complex, overly written bullshit? Seriously, even someone like Grant Morrison couldn't write something more hard to follow and also just plain shit if he tried. It is also directly responsible for dextroying several comics that were completely unrelated to the run (I will never forgive them for ruining the very good Supergirl comic by making her "infected" by the events of JL, which were completely unrelated to her book).
Fuck that JL run, from the idiotic bullshit about the Source Wall, to introducing the Monitor's fucking mother, which is so fucking stupid it feels like something Hickman would have written it if he was a DC writer. Even the New 52 JL was better written, and I considered that to be the worst run in the history of the Justice League until the current bullshit.
I actually think the Justice League was one of the things that improved with the New52, and Snyder's work over the past ten years has been pretty amazing. His run on JL is not hard to follow if you read it and is one of the best runs of Justice League stories ever. As for Supergirl, that infected story had nothing to do with Justice League--you are think of Batman Superman.