Maybe also because one holds it in the same position, where other tools
are rotated or picked up repeatedly?
And it is hot so there is a certain interest in not dropping it -
tighter grab.
It is so trivially easy to _NOT_ get carpal tunnel syndrome, that it
almost breaks my heart to see the way people hurt themselves.
I have been in situations that have been blamed for CTS, (keyboard, mouse,
screwdriver, video games, soldering iron, pen/pencil, etc, etc, etc) and
I've felt the strain on my tendons, and rather than "play through the
pain", I rearranged the orientation of my wrist until it didn't hurt.
Duh.
Pain is Mother Nature's way of telling you, "Don't do that".
Of course, if you're in denial of the messages of your body, then you'll
continue to abuse yourself.
Good Luck!
Rich