The NEC is full of confusion...the old 'grounding or bonding' issue abounds.
As a "simple mans' rule,' when I get confused I ask myself "is this wire for lightning protection?" If so, then it's a 'ground.' If not, it's a 'bond."
Using this understanding, let's consider the wire from the panel to the water pipe.
In an old house, where there is no ground rod, this is a 'ground wire' or GEC.
In a new house, this wire is there to clear any fault current to the plumbing- so it's a bond, not a ground.
Probably over-simple, but it does help me keep focused.