Ash has transcended the need of barbaric, primitive lust. His soul is pure and is mind is focused, focused on one thing:Being a Pokemon master. Plebeian love and emotions are simple obstacles in the way of that goal.
They contribute nothing to his ultimate achievement. Ash recognizes this, therefore he casts away any perverted feelings he is exposed to. He rejects the very fabric of his biological machine. For Ash is not an every day man working the grind of life, he is a beacon of purity and spirituality, he knows what it takes to be a Pokemon master, he makes the sacrifices and pushes on.
All men should strive to be like Ash, to put aside fruitless female attentions for the greater noble goals which rise past them. For once Ash truly does catch them all, will he not have an even greater array of female attentions? His foolish companion Brock fails to understand this, because Brock is a mindless sheep, a slave to his instincts which no longer need apply in our new world. Brock is a failure in his own right, he will never dream a goal grander than that of sleeping with females, he is nothing compared to Ash. Ash is god. Ash will succeed.