Which I had never noticed back in the day had a lot of adult humor like looney toons until I re-watched it when I was older.
I certainly wasn't expecting it to become much of a conversation topic myself.
Maybe it is a matter of where the hand is gesturing for a moment that makes it seem feminine to some people? Even if it is for a moment, people do tend to follow a gesture to something with much more focus than we realize. A female's hips tend more noticeable than a male's often thinner, straight hips while a male's upper body (like their arms) tend to be larger than a female's more often than not.
That said, personality and a person's physical appearance can play just as much of a role in how a gesture it seen. Take a habit I share with my friend: crossing our arms while looking straight at someone when we know we are about to be displeased or don't agree with what the other person about to do or say. When my friend does it, people see it as a pout and oddly cute due to their small build. When I do it, however, despite being described constantly as looking much younger than I am (and not being that tall either), a good deal of people have found the gesture to be more intimidating due to my more stocky build (a number of pointed out that the muscles in my arms become more noticeable when I cross them). We both do the the same thing, but people see the actions somewhat differently due to how we look physically and our personalities (they are much more extrovert and expressive than I am).
There's a lot of factors that can make a gesture seem 'masculine' or 'feminine'. But a culture's views, a society's own focus on matter of gender, and deeply ingrained preconceptions do play a pretty big role on the matter. It is a personal matter at the end of the day how we choose to be seen ourselves, whether other will agree it's how we're supposed to act or not. I can't count the number of times I was constantly told not to do certain gestures or postures because it was 'not something those of my gender did'. Luckily, most people have give up trying to tell me how I'm 'supposed' to standing and such.
That being said, I do enjoy the Detective's habit and hope someone lampshades the fact that their hands being on their hips means sass is very likely going to follow the action.
I don't know if I'd call it a good catch since I still have absolutely no idea what is likely going on with Felix/Farah and Morgan/Manson's reactions. Nate/Nat and Ava/Adam are surprisingly both open in a way that make it somewhat easy to guess how they're feeling about hearing the Detective's voice. Meanwhile, we have these other two that come off more as wild cards themselves, but for different reasons.