Eating mangoes with skin intact I grew up in a family where we had mangoes with the skin intact in fruit salad.

After I got married, I was exposed to the "fact" that "nobody" eats the skin of mangoes.

It is true that I have never seen anyone else besides my childhood family eat mangoes, which would explain why I have no idea that you would not eat the skin of mangoes.

Perhaps, my childhood was too impoverished that we even ate the skin of mangoes. Perhaps, eating skin of mangoes is not an unusual practice, I don't know.

A reason that seems valid is that there is too much chemicals on the skin. But then we would have to say that about strawberries, peaches, apples, wouldn't we?

And what about people in India, China, Japan, Germany, Indonesia or Brazil? Do they eat mangoes with the skin?

It seems such a waste not eating the skin.

Q1. Is it unusual to eat the skin of mangoes, unusual to include mango skin in fruit salads?

Q2. Does mango skin have more chemicals than the skin of other fruits, which we have to eat with their skin intact.
It's not about chemicals on the outside of the fruit; washing the fruit well should take care of that. Whether we eat the skin of any given fruit basically boils down to whether it a) tastes good and b) has a pleasant texture. For example, some people eat the skin of the kiwi, despite it having a hairy texture that many people find unpleasant. Many people do not eat the skins of mango because it tastes bitter and has a tough, fibrous texture, but if you don't mind the texture and enjoy that taste, go ahead, enjoy :)  

Note: I'm seeing sources that say if you're particularly sensitive to poison oak, you should not eat mango skins, as they contain one of the chemicals in poison oak but in a much lesser quantity, so it might cause an allergic reaction. You'll probably also break out from touching the mango skin to peel it, so take that as a warning sign. This doesn't apply to the OP, since if you've been eating them all your life you're obviously not allergic, but might apply to other people googling this question.