JL felt like a committee of suits sat down and watched all the MCU movies and wrote a list of everything they liked about them, and then showed it to the makers of JL and said, "We want all of this in the JL film." Wisecracks, check. Young guy gets mentored by older guy, check. Tough female who's as good as the men, heroes fight each other first then fight somebody else, CGI alien invasion, villain with unclear motivation, pursuit of a magical maguffin, check, check, check.
Basically when they focus on placating people rather than telling them a story, you wind up with garbage.