It's a very recent trait evolutionarily but seems to predate deliberate alcohol production for the most part. It's been thought that when the human population became very small during an ice age, the ability to eat old fruit under snow might have been very important. But you're right, populations used to deliberate fermentation for thousands of years, such as in China seem to be much better protected.

Also that American Indians seem to have less of a tolerance to it, as alcohol was fairly unknown before the Europeans came.

Whereas, middle and South America did have a tradition of alcohol in Pre-Columbian times. However, alcohol was often exclusively reserved for those who had attained extreme old age.

Alcohol was probably the only safe beverage to drink, as the alcohol would kill pathogens. Even safer than water.

I've heard that's why sailors drank a lot of rum in past times. But I don't know if it's true, or if sailors actually drank a lot of rum.