Originally Posted by omegadiamondzinc
why do people not understand that her q is magic dmg and can't crit
Q doesn't crit, the autoattack that applies Q crits.
He's probably hitting for 1000 because of a combination of a normal autoattack crit, the Q, and the Trinity force proc.
One reason you'd want to go AD is because you want to jungle at level 1, build a Wriggles Lantern, and solve some of her farming problems and staying power, or get a Madreds Bloodrazor which complements her Q (i.e. % HP damage).