Im guessing its because when she entered the house, she asked why did Kayako kill her sister and the others.
Therefore, Kayako showed her, or rather, killed her in the same way she died, so that Aubrey could understood the pain and hate she felt. The pain and hate she felt, then turned Aubrey into another part of the curse, one because she had been killed in a 'fit of rage' and two, because she's reacting the way Kayako did.
She does, Kayako killed everyone in the same way, that's why they dissapear because she drags them in to the house and repeat the same scene when her husband killed her.