How is cannabis able to take high temps outdoors in summer, but not indoors?

[Compost Man]

A buddy of mine asked me why cooling was such a big deal in the grow room, his point was that outdoor plants do fine in the summer heat. I had no idea how to answer that, never thought about it.
In my area it gets 100 and above quite frequently in the summer, but plenty of people grow herb and do fine. If it were to reach 100 in my room my plants would die, how is this? I have a feeling it has something to do with light intensity but I'm not sure. I tryed goggling this with no luck.

Ones natural ??