Your problem is denial.The problem is,
You're using that to make a case on another passage in the Bible where skin color was not mentioned nor implied.
You then try to get around that by recontextualizing even other parts of the Bible, not even relating to this part, to make it appear that the environment or circumstances would lead to it being about skin color.
So then you ARE debating cain's color.
There is leprosy.
There is leprosy with light colored and rarely actual white coloured patches of skin except in the case of some scarring where a limb at some part was lost and cut off.
BUT THERE IS NO SUCH THING AS TOTAL SKIN COLOURED WHITE AS SNOW LOOKING LEPROSY. It doesn't exist. I can't even find a picture of a person with leprosy who has just a large or medium size patch of white as snow leprosy. Even small patches are hard to find and there's thousands of pictures of lepers on the web.
The man was cursed with leprosy. And the man's entire body was changed to what we would call 'white leprosy' if it was to be described. That 'whiteness' was a second curse because...wait for it...because....BECAUSE LEPERS REMAIN THEIR ORIGINAL SKIN COLOUR. They don't become a leper and turn pink or tan or white or yellow or any other colour. A black leper stays black. A yellow leper stays yellow. A Caucasian leper stays Caucasian, etc, etc.
Having his skin turned white as snow means he received a secondary curse on top of being cursed to be a leper.
Deny that information all you want.