absolute scales are still arbitrary. you would probably want to use a scale that measures "perceived heat" which is different than average kinetic energy
Kelvin is just our word for it, but that is the point of “no heat”. It isn’t arbitrary, there is no “negative kelvin” just like you cannot make something colder than absolute zero.
So if you take the difference between “coldest possible temp” and “average summer temp”, then slice it in half, you’re getting temperatures that would kill most life on earth.
Just to nitpick, there are negative kelvins. I don't really understand it, myself, but I know it exists due to the specifics of how temperature is defined. Negative kelvins are actually extremely hot.