It's not destruction per se that delights you, it's justice? And righteous destruction is overdue justice writ large and clear.

Well, I think, me too.

"Good" thing about it? The pleasure of (sane) morality. Justice wish fulfilment implies justice wish.

"Bad" thing about it? In reality, very few groups are so bad that annihilation is the best fate for them. The good people among us have probably evolved from groups that seemed irredeemably bad. Taking pleasure in the Smiting Arm of Justice hardens us against our compassion. Our desire for simplicity can lead us to be simply wrong.

So, as fantasy? Yay! If it were to happen in reality? We should weep.