Not marketing Superman was ridiculous in hindsight, but to be honest WB have no-one to blame but themselves for allowing Snyder to kill the character off in BvS. I'm never going to understand that decision for as long as I live because they effectively painted themselves into a corner. There was honestly no winning for this movie, no way for it to overcome the mistakes of both MoS and BvS.
It frustrates me to no end how WB chose to build this universe on such flimsy foundations. 5 years of bad creative choices, of behind the scenes drama for nothing. And it all could have been avoided, that's the worst thing about this situation, it was all avoidable. All those arguments in the DC film forums over the years was about this very situation. Only it's 10 times worse. JL should have been one of the biggest movies of all time, and would have been had someone at WB just used some common ****ing sense. These characters deserve better than this.