That Rotovac article says that rotary methods CAN distort pile , not that they will .
An experienced and trained operator will not do this , in the same way that an experienced and trained HWE operator will not overwet a carpet ,causing equally bad damage to a carpet backing .
I know it is easy to produce studies to assert any viewpoint ( goodness knows Chemdry produced plenty supporting bonnet methods) I think it is a case of common sense , lubrication and proper care being taken.