The author gave no evidence that spiders evolved. He just assumed they did. He even spent time writing about what spiders may have been like as they evolved. However, the whole article was, in reality, an article on the powerful evidence for creation. The Scripture is plain.
People deliberately reject the truth and become blinded.
In other words, the real reason most scientists are evolutionists is spiritual, not scientific. This is why we should be very wary of any idea about life that has a consensus among non-Christians. Sadly, many Christians listen to the ideas of secular scientists and try to add these to the Bible. We should also remember this the next time we listen to the media discussing the topic of origins. Most of the people in the media in the Western world are atheistic.