Being tall had several competitive advantages in the past. Basically before guns were invented the bigger guy usually could kill smaller guys, and get more food for the family. Quite obvious that women would prefer the big guy, and instincts don't change that quickly.
I perfectly agree it make sense evolutionarily speaking, I just wonder how that subjectively manifest in a woman mind. I don't think it's the same perceived stimulus vs the consensual sexy perception of a hypertrophied 6 pack.
I think they actually change faster than most would think. While that specific reason for preferring big guys is out-dated, more recently malnutrition and destitution have been a black mark on short people.
The reason I think societal trends move faster than we think is that I think it was only in the middle of the last century that we still preferred fatter bodies.