I'm not an advocate for Morris, you're missing the point entirely.
Harding sullies his scientific argument by not remaining agnostic. That's not irrelevant, that's a major source of the contention with literal Creationists.
Do you want the Creationists' ears open or closed?
If you want them open, why close them with the gratuitous inclusion of the "irrelevant?"
This is turning into, "That's not how you reach literal Creationists."
You don't reach literal Creationists. I'm here to tell you after over three years of throwing the whole pile at them day after day, you just don't reach them. That's a fact. It's not a consideration in writing articles against their arguments. Rather, it's a fascinating area of Abnormal Psychology.