That's cuz Zack Snyder sucks and Joss Whedon was a poor choice to bring in to try and fix a Snyder established universe instead of having him create from scratch.
JL was going to fail regardless. It was predestined. When BvS didn't make at least a billion the writing was on the wall for the outcome of all Snyder related movies.
With more hindsight and retrospect I think WB thought they had the next Bay with Snyder's all style and no substance approach where lack of actual substance can be made up with directly adapting random iconic DC comic panels to film in lieu of narrative/theme/story structure.
And that's just a glimpse of Snyder's decision making and imagination when he has creative control. Its one thing to decide to make a Dark Knight Returns movie adaption. Its even one thing to introduce a darker more edgeir Superman. Its an entirely another to have a Superman origin movie with **** messages like human society sucks don't show your powers and let loved ones die, have Superman murder the villain and present it as the only solution, and grandiose 9/11 imagery in the final act and THEN after introduce an older Bat**** insane Batman that's hellbent on killing the threat that is Superman cuz.
All of that is **** Snyder's idea (Managed to even damage Wonder Woman in a smaller role to the point it has to be ignored). With no correlation or resemblance to the comics. Not even Elseworld stories I think
The best parts of those two movies are a Batman warehouse scene and ****ing Russell Crowe on a soon to be dead Krypton.