Because I am tired of terrible TCO duelists. Sturgeon's Law is applicable; 90% of TCO duelists are crud. Now, I won't name names.
Don't use them...That is all...
Your deck is hybrid if it has any one of these traits:
- More than 40 cards, discounting psychic creatures
- Uses cards in the Hall of Fame at an illegal amount.
If you break these rules and clusterfuck badly, you are officially using a hybrid deck and are fair game for the unfun overpowered techniques many good hybrid decks offer.