>>>Isn't it a fantastic claim to say of all the people who lived in the history and believed in a deity that they are and were delusional?

Pedant alert: If they are dead they aren't anything, you have to use the past tense.<<<

Try reading til the end of the sentence, the second last word is "were."

>>they are and were delusional<<

Those that are alive are delusional (supposedly);
those that are dead were delusional (supposedly).