I don't know enough about Agassiz to even know if he was actually a Christian (there's a huge gap between all those who claim to be, and those who actually are Christian), but your reference to him is still irrelevant, because he has no following nor influence.
Certainly, you can point to racist Christians, but as I stated previously, they don't have followers a hundred years later.
I'm not saying that anyone who believes in the deductions based on the guesswork of Darwin is a racist, as he was, but my point is that his devotees have a religious fervor that even the right wing fundamentalists can scarcely match.
It's a faith, and he's the founder. You may not be one of the faithful (I don't know that), but there IS a faithful, and they will fight to the finish for their beliefs.
Oh, please. Charles Darwin is regarded as the father of modern biology, but biologists don't worship him any more than, say, chemists worship John Dalton or Antoine LaVoisier, or physicists worship Issac Newton or Albert Einstein. Claims that Darwin was a racist do not hold water. Though some Darwins chauvinistic Victorian attitudes may seem quaint by today's standards, he was not a racist by any stretch of the imagination. Like most British, he strongly opposed slavery and supported of the Union against the Confederacy in the American War Between the States.