Have you previously paid any attention to the permissions the Facebook app asks for at all?
I wanted to install Facebook on my Android device so I could share stuff on Facebook via the native "share" intent. Seeing the permission list made me reconsider.
When they broke messenger off into a different app I uninstalled. Right now I only use the mobile browser version and really only to upload photos of my daughter for my family to see. I'm starting to use it less and less though because the browser version is terrible.
If you're on Android, try using Tinfoil. It's the same browser version (so it may still be terrible for you), but interacting with it is a little easier than just opening Chrome/FF and going to fb.com.
I wanted to install Facebook on my Android device so I could share stuff on Facebook via the native "share" intent. Seeing the permission list made me reconsider.