[snarks_when_bored]

It's not written to convince the creationist that darwinism is wrong...

Creationists don't need to be convinced that Darwinism is wrong—they already believe that. Perhaps you meant that the book's not written to convince the creationist that Darwinism is right. If so, you're correct; the authors are doubtless aware that creationists are largely impervious to evidence and argument.

[beezdotcom]

that creationists are largely impervious to evidence and argument.

A gratuitous generalization. But that's not uncommon, these days.

[Dataman]

the authors are doubtless aware that creationists are largely impervious to evidence and argument.

Impervious to non-existent evidence and feeble fallacious arguments. Remember-

all evolutionists have to do to win the battle is actually produce that mountain of evidence they claim to have.

But they don't have it so how can anyone be impervious to it?

BTW, your argument is actually a straw man fallacy. Creationists are impervious to such fallacies, which seem to be the best arguments evolutionists can muster.