You know this is ad hominem (to the man) and therefore irrelevent.
No it is not irrelevant. It is imbued in the whole philosophy of evolution. Darwin was an atheist but deceitfully hid it from the world throughout his life. In other words, he was a liar. That may be an attack on his character, but it is not an ad hominem. It is a factually correct statement.
Sigh. So much ignorance, so little time. ad hominem is a fallacy of irrelevance. The truth or falsity of an irrelevant statement is, well, irrelevant.