Why are caffeine and alcohol drinks considered "diuretics" in a negative way, but plain water makes me pee more?

I drink coffee for the first few hours of my day and usually drink beers for the last few hours. I'm an adult. I piss a few times, no big whoop. If I have a glass of water, say, to take pills, in half an hour I urgently have to piss a glass of pee. So fine, I drink more coffee, do my day and all. Urination is not a problem. Take a sip of water before bed? In 20 minutes my bladder is whining! I have to unload that sip of pee.

Why are beverages denigrated as nasty dehydrating "diuretics" when plain water (my third most consumed drink) seems to run right through me and cause a stronger urgency to pee?