I see what you mean. These were shot horizontally for a reason - not just because it's easier to shoot in horizontal format. I think this is what people were arguing for/against.
Nobody said you couldn't ever shoot horizontal portraits. There just has to be a purpose to it besides the fact that the photographer forgot to turn the camera! 
.
I do have to admit that in the beginning I shot a lot in horizontal format just because it was a huge PIA to shoot vertical. It was awkward feeling to shoot vertical! But hey I am a MWAC!