your "education" provided by commercial antenna manufacturers and "hobbyists" is in error, the opening statement is irrefutably correct.
maximum feedpoint current (low impedance) only occurs when the 1/2 antenna is center fed, when end fed feedpoint voltage is maximum. (high impedance)
from the center of a center fed dipole the impedance increases in direct proportion to the shifting phase relationship between current and voltage as they move towards the ends of the dipole elements. this is perfectly understandable once you realize the impedance is simply a mathematical ratio between the two.
here is the relationship expression based on 100W input to a reflectionless load in a 50 ohm system.
E / I = Z
E = 70.7V
I = 1.414A
Z = 50 ohms
both current and voltage are in phase with one another in this 50 ohm system.
there is also a mathematical ratio expressed when voltage is divided by current.
70.7 / 1.414 = 50 ohms, the ratio between voltage and current is 50:1.
this same E/I relationship also exists in any feedline that is terminated with a perfectly matching load. when this is not the case, the relationship between voltage and current all along the feedline changes in direct proportion to the mismatch (phase shift) resulting in reflection from the load and the ensuing standing waves on the feedline.
the impedance of the feedline is no longer 50 ohms at every point along its length.
