This statement doesn't jive well with how variable any given population can become, especially when under duress. These people are all biologically identical:
A biological distinction doesn't have to exist for a population to self-express in entirely different ways.
It wouldn't be shocking to the senses if the HE's, having shifted their collective priorities away from magical ability and towards combat proficiency, present as being more physically robust than their kinfolk-in-red -- more fully cultivated by strenuous physicality. This militarism, in conjunction with a necessity to maintain allegiance with the Alliance, could easily be cited as explanation for the motivations of the HE's having clearly deviated (this process become more rapid recently) from venerating the
creations (i.e. things, like Silvermoon or Sunwell) to exalting the
creators (i.e. themselves, whatever they create going forward).
A model which is structurally similar, but more pragmatically athletic, and a culture which has chosen to distance themselves from things they had no part of (instead of retroactively laying claim to the achievements of their ancestors) -- on paper, this is strikingly different from Blood Elves (and Void Elves, who present as being BE's without common sense).