There are those that would say no motorcycle with "Sport" in it's name should ever weigh more than 600 pounds, or have a drive shaft.
There are those that would say no motorcycle with "Tour" in it's name should ever come without full luggage, a large windshield, shaft drive, a centerstand, cruise control or carry less than 5 gallons of gas in the tank
The sport touring market is a weird one, in that people want the best of both worlds when that is literally impossible, so manufacturers do the best they can.
The MG above is not a "sport" bike (weighs too much and has shaft drive), and it is not a "touring" bike (not enough ammenities), so what is it?
Stick some soft luggage (or hard if you wish) and it pretty much fits the bill of a sport-touring bike. Relatively sporty but still capable of light touring.
One of my favorite sport-touring bikes I owned, was a Gen 1 FZ-1. Light weight, big power, nearly 6 gal gas tank, small fairing & shield, center stand. I liked it a lot. Throw some soft luggage on it and ride it cross country if you wish, and still plenty sporty in the curvy bits with 125 hp and weighing in at 458# wet. In order to put more "Tour" in it, with hard luggage, shaft drive, cruise etc it became an FJR, also a nice, bike but then it weighed over 630 pounds, which took a lot of the "sport" out of it.
Sport-touring bike...hard to define, even tougher to build.