Besides, by focusing 100% on this physical aspect you're nearly just attack a straw man argument and ignoring the substance of everything else. Not every person is exactly the same and it doesn't matter. Get over it.
Work under a hot engine bay for 8 hours: no, but I've worked outdoors carrying construction material during heat waves, and I've worked indoors in cold data centers.
Holding my hands over my head until pain develops: yup. I don't recommend it to anyone.
Used an angle grinder: no. I have used lots of other power tools. Should you trust me with one? Not until I'm trained on it.
Lifted 300lb pieces of granite: no. We have these things called wheels, you might have heard of them? Using wheels and levers and ropes and pulleys, I have moved much heavier things. I recommend using appropriate tools. Hoists? Cranes? Block-and-tackle?
Modern mining is done primarily by machines which are tended to by mechanics. Ever wonder why there are so few mining jobs these days? That would be automation improving the efficiency and taking away manual jobs.
Speaking of which, truck drivers... will be obsolete soon. Even so, driving is not a task that inherently favors upper body strength.
OK, so the physical argument holds no water. What's left? Prejudice and social expectations -- which is to, say a prevalent institutional bias.