I liked Captain Marvel & Wonder Woman but not this

Because as a heterosexual male I don't like chick flicks.
Captain Marvel & Wonder Woman weren't chick flicks, although they had a female lead. Also, they weren't comedies.

This one was. They targeted females, especially young females. I don't have a problem with that. But it shouldn't come as a surprise that it would flop among males.
Margot Robbie's Harley Quinn will be first and foremost seen as sexy, not funny, not bad ass. This movie tried to make her funny and bad ass, but it didn't go down that well.

Is it the worst movie ever? No.
But I can't think of a DC or Marvel movie that I've enjoyed less. Besides Batman & Robin.