I did. Scroll up. I quoted the same thing twice because you evidently didn't read it the first time.
The UESP isn't he best source. Use The Imperial Library instead.
Even if Bretons came from Nedes and Aldmer, they should still be taller. Nords are the closest genetically to Nedes, so they had to have been tall (at least taller than Imperials), and Aldmer were tall.
The Nords aren't closest genetically to Nedes. Nedes are the native men to Tamriel. Nords are from Atmora. Nibenese, Breton, and the Kothringi are the closest genetic relatives to the Nedes. The Nords have always been different than the Nedes for a long time. It's like saying I am Argentine which is decended from the Spaniards thus I am descended from the Italians. The Nords and the Nedes are different, and Bretons descended from the Nedes.
Read my former post about the Aldmer. Aldmer does not equal Altmer, and as Altmer is the only Mer that is especially tall, it seems to me that the Altmer grew taller.