You have to admire their (completely non-speculative) reasoning in the article about whether Jesus was embalmed too:
In order to treat Jesus’ body, for instance, Nicodemus provided a large quantity of spices for this purpose. (John 19:38-42) Why so many spices? Heartfelt love and respect for Jesus may have moved him to such generosity. We need not conclude that such a use of spices was intended to preserve the body.
Yes, the rock-solid evidence here from which we can conclude that Jesus wasn't embalmed is that Nicodemus was a generous guiy.