Totally agree.
To be honest, I have no idea what the Harley Quinn plot was and why she fucked that president of whatever country they were in. No fucking clue how that played into anything. It's just the same as Black Widow - the plot about the red room, I have no fucking idea what they were doing, the movie was about family!
Harley Quinn fucking sucks. Period. Birds of Prey was probably the 3rd movie of my life I've ever walked out of (1. Public Enemy, or whatever Johnny Depp 1900s robber movie, 2. Thor 1 {and I later regretted and love the movie now}, and 3. Birds of Prey) because it was so awful. Margot Robbie fucking sucks as Harley Quinn, or the character sucks, whatever. But her voice, etc, it's just fucking *garbage*. The only remotely good scene is in the even shittier original Suicide Squad where she's changing or something. Other than that, Margot Robbie was great naked in Wolf of Wall Street, and great as Tonya Harding in "I, Tonya". But she fucking SUCKS American Inventor DICK as a comedy / dark / good bad guy.
You're absolutely right the rat catcher back story was awful and killed pacing. A movie like this needs to be 90 minutes, and every scene moving things along and being awesome. This had so much crap in it.
But it bothers me, because John Cena was fucking awesome and is truly funny, Idris Elba was fucking good, Polka Dot man was great, Shark ripping people in half = awesome, and the guy from For All Mankind was so good. But yet the movie sucked. That shit pisses me off. Like how Wonder Woman was so fucking good, and Gal Gadot was phenomenal in that movie and as WW in BvS, but then WW84 comes out and it's so fucking stupid, she sucked, everyone sucked. But I don't blame the actors, it's the material. You can't turn chicken shit into chicken salad.
SIGH. I wanted this to be FUCKING AWESOME so bad.
Edit: And they killed Weasel, who was literally like an instant fucking amazing character. What a stupid decision, Gunn's brother is fucking hilarious and they didn't feature him. He's one of the best parts of GOTG2.
EDIT2: Anyone else notice that "JOTENHIM" or whatever sounds like Odenheim or whatever Thor's world is?