Didn't even think about the drug angle but yeah it's a club so the probably do deal with drug use and dealers in the bathrooms. Was probably doing something really suspicious in the first place. If the manager knocks on the door and then asks what you are doing and takes your purse then there was probably something weird going on.

I figured all I would have to do is pause the stream, tell this lady I was peeing and I'd be done in a second, and I could finish my business. ... So I paused my piss, and opened the door and was instead greeted by the manager, Karen, who proceeded to forcefully take my purse, and then told her lackey next to her to "Search his bag." and he took off outside to rifle through my belongings.

So if you are peeing, how the fuck long does it take to finish and why would your solution be to clench mid stream then open up the door to talk to the person while sitting on the toilet? None of that makes even a tiny bit of sense.