The factory tires on a Kymco scooter may not be the best on the market, yet I have never heard they were unsafe, like that mess that happened to Ford quite a few years back over the bad run of Firestone tires.
A first rain will wash up oils and grease from the roadway you wouldn't necessarily notice.
Black ice is a bloody nightmare !
From my experience, loss of traction at the front will cause the machine to wash out and pretty much flop.
Problems from the rear will send you off sideways, perhaps where you may have the front end turned full lock and still travelling straight forward !
Any time I might be concerned about possibility of a slick surface I apply the brake in short pulses, off and on, until I can tell how things are grabbing.
Still, I've gone down more than a time or two.
I don't use my rear brake much... mainly as an assist to the front, or to keep the back in line with the front.
Easier to change front disk pads than rear shoes, anyway...
I've never had ABS on a two wheeler.
It's generally best to put new tires on just before a rainy season begins... if possible, so you got the best on the ground, where it counts.
Glad you weren't injured and damage is low !
redk