RonD, I do not own, nor have ever owned, a Ninja 300, or any Kawasaki ever.
I have ridden motorcycles off and on road for the past 39 years though, everything from 50cc, 125cc, 250cc, 500cc dirt bikes right up to varying sizes of street bikes, up to 1200cc.
My personal ride is a 1999 Honda VFR800 that I have completely stripped to the frame and customized with upgraded suspension and a ton of other cool stuff.
It "only" has 100 HP and "only" does about 155 MPH. It has about 60,000 miles on it. I can afford to buy any bike I want, tomorrow, but I don't need anything with twice the horsepower, even though I know I can handle it with nearly 40 years of riding experience.
I've ridden all across western Canadian provinces and western USA plus a crossing of the us to North Carolina. Hundreds of thousands of miles put on several different bikes that have occupied my garage.
And I've crashed before, so I know how much it hurts.
I'm not a purist, but there are some trends that tend to run common in the motorcycle world.
Brand new rider, buys the fastest bike possible. Can't afford leathers so he rides without.
Doesn't realize how heart attack serious a 170 hp 400-something pound bike is.
If you're lucky, and lose the front in a 30 MPH corner and low side it, count your blessings.
If your not lucky, and crash out at triple digit speed while trying to see "what she'll do" (in this case about 185 MPH) then maybe we will see you in the next world.
And yeah, maybe there is that one guy who bought a litrebike as his first ride and live to tell, but it's generally a bad idea.
Starting small and working up is always a good idea. And it's way more fun to ride a slow bike fast than it is to ride a fast bike slow.
Graduated licensing restricting new riders to smaller bikes for a defined period of time would go a long way towards helping eliminate the trend of new riders getting in over their heads with immensely powerful and fast bikes.
/soapbox