JL was bad, sure. But after what we got with BvS, the ones who were put off by it expected this. We were prepared. BvS is really where the damage made itself known. MOS was teetering between good and bad film (I still think its solid despite the serious problems I had with it), but there were enough promising elements for WB to move ahead with Snyder, I guess. Or it could just be that no sane/respected director would work under the conditions that Zack had agreed to when they finally convinced him to take the gig. Also can I just mention how sad it is that he was one of their last choices, he didn't even want the job at first, they finally convinced him and here we are.
They went from MOS which was supposed to be a standalone superman universe, to a full on DC Movie Universe. If I remember, MOS got delayed in 2012. Avengers dropped that summer, and WB had its heart set on the connected stuff. It was all ill conceived from the start. They saw the success of the dark knight trilogy and thought they could do that with superman. All changed with that delay and Avengers though.
They could've released a good JL movie but the interest still wouldn't have been there after the absolute dumpster fire that was BvS. The general audience really did not like nor connect with that movie. The brand isn't damaged beyond repair, but they really need to look at these properties in a different light. Get people who understand/love these characters. If you can swing a big name director/writer to make a film, thats great too. They shouldn't settle on someone just to meet a deadline or be worried that they'll miss the boat on a trend. Just make good movies and let things happen naturally. Sigh.