Why it is socially acceptable to make jokes about pale skin while making jokes about dark/black skin would be offensive?

I come from a Mediterranean country where people are supposed to be tanned. My skin has always been very pale and takes time to get colour. All my life I have dealt with offensive comments, jokes and stupid questions about my skin colour. Mostly from other immigrants of darker ethnicities. It got to the point in my teens where I was embarrassed to show my legs because they looked too white. I really want to know why all this behaviour is okay when if it was the other way around it would be considered racist or offensive.

I also don't understand what it is about people in general that skin colour is so important. Luckily I now live in a country where the sun hardly ever appears and I feel a bit more on par with the people. Yet I still get asked if I'm really from where I come from🙄