inside the poker mind

im reading this book and i come to a section on AQo it talks about how its not a great hand to call an early postion raiser i do see how its most likely that the raiser has AA-QQ or AK but couldnt he have worse hands like KQs if hes a little loose .. or maybe JJ -99 and you would have a horse race to the flop .. i dont know im confused and i just look at KQ and AQ AJ as good hands to raise with in early posistion in an un-opened pot or to call with ..with a raise from middle position. poker is sooooo situational and im sure im being vague ...id like some help .. thank you