I've been trying to put together an answer but each time I'm about to post it I need to change it based on your continued edits. This answer assumes you are complete with your last edit.
The Skinny on Potentials: remember these three key facts: 1) A
positive charge moves from high potential to low potential. 2) A
negative charge moves from low potential to high potential. 3) In
either case, the electric potential energy decreases, as it is
becoming kinetic energy.
This chapter is defining high and low potential based on the conventional definition of current, that is, the flow of positive charge.
Regarding statement (1) It requires external work to move positive charge from a negatively charged region to a positively charged region. That work raises the potential of the charge. Consequently the positively charged region is considered at high potential. Then of course, positive charge moves naturally from high potential to low potential.
Regarding statement (2), although negative charge moves naturally from a negatively charged region to a positively charged region, it is misleading, if not downright incorrect, so say negative charge moves from low potential to high potential. As far as negative charge is concerned, the negatively charged region is high potential and the positively charged region is low potential.
Regarding (3) it is correct that positive charge moving from a positive region to a negative region, and that when negative charge moves from a negatively charged region to a positively charged, there is a decrease in potential energy. But that doesn't make statement (2) correct for the reason already stated.
What causes current? Why does an electron drift through the circuit?
It's because there is a difference in electric potential (voltage)
between the ends of the wire. Negative charges naturally move from
regions of higher potential to lower potential. Voltage creates a
current.
There is nothing wrong with this statement, provided that the statement "Negative charges naturally move from regions of higher potential to lower potential" is coupled with the understanding that, for negative charge, higher potential is a negatively charged region and lower potential is a positively charged region, for the reasons already stated.
Hope this helps.
