Here's why:
* Cybernetic Magician's effect: It reads "During your odd turn, you can send 1 Spellcaster-Type monster from your hand to the Graveyard; draw 1 card."
* "Odd turn" restriction: The effect specifically states it can be used during your odd turn. This means it cannot be activated during your even turn.
Therefore, you can only activate Cybernetic Magician's effect when it is your first, third, fifth, etc. turn.