Holding down shift is not really a problem for constant names since you need it for the underscores anyway. You can type CONSTANT_NAME without lifting the shift key but with caps lock you still need to use shift anyway.
To be fair, on some keyboards, including the one I use, it's easy to reach both the right and left shift keys, so it's easy to alternate shift keys as needed to avoid using other fingers or moving your hand from the home row.
It's probably fairly obvious what I think about the taught-at-school touch typing method. It's a decent middle-of-the-road option that's intended to be easy to teach and to work for most people in most situations; that's all.