Do I know this heretic personally? Does he or she post on Free Republic? Is it good weather for an outdoor fire?
My guess is that thoughtful people interested more in conversation than contention understand that 600 or so years ago the very idea of religious pluralism and of the toleration of wide range of beliefs was as uncommon as thinking that slavery was in almost every case evil.
Now, as then we find treachery and spying for the enemy horribly vicious and harmful to the general welfare, so those who want to understand those with whom they disagree can see how reasonable people of good will could have thought what Aquinas thought.
I think annalex agrees heretics (I am one) should be executed. Do you?