Black usually pushes c7-c5 and b7-b5 against KIA to grab some queenside space and some counterplay there. If he dares to castle queenside while rolling his queenside pawns, that would be suicidal. Just open some lines on the queenside and his king would be in imminent danger.
If he does not roll his b and c pawns, and he castles long, I suggest you to try grabbing some space in the queenside as well by means of c2-c4 and b2-b4. Black would have no play in any area then.
In the KIA, White focuses all the pieces on the kingside, aiming for a direct attack on Black's king. But what does White do if Black's King castles queenside, avoiding the kingside attack?