Because decent people hold misreprentation in contempt, even (especially) when it's done for a Holy Cause.
And oh yeah, no scientist has ever suggested that mammoths have been extinct for even millions of years.
Their mind is made up, don't confuse them with the facts.
Science has always maintained man and mammoth co-existed... and their extinction was likely due to overhunting by man.. not millions of years in the past, but in recent history. In North America, after Humans crossed the land bridge from Asia... but again, don't confuse em with facts.
I have found that the facts in the creationist/evolutionist debate fall on deaf ears, particularly on the anti-evolutionary side of things.
I find it quite amusing since Even the Vatican has embraced Evolution as a viable theory and not in conflict with the faith..
After all, change is the very evidence of God's existance. Nothing changes without something else first acting upon it to force that change, and that even was acted on by something else... etc etc etc back to the creation... and that first mover is God in the judeo/christian world view. Why some folks believe change is somehow a threat to religion is beyond me, its primafacia evidence of God himself.