You don't contract gingivitis over night. That's like telling your wife you caught gonorrhea from a toilet seat.
It's caused by long term lack of proper oral hygiene........Specifically, poor brushing habits and lack of regular dental office cleanings leading to plaque formation. Followed by tartar build up over the plaque and spreading under the gums then end game of gingivitis...........
So my advice to you is, brush your teeth and see your dentist twice a year...........LOL!
Well, my previous cleanings (every 3 months for the last 15 or so years) didn’t detect it, but I will bow to your much superior knowledge. I must be terrible at brushing my teeth.
Kiss my hairy posterior, FRiend.