That blog post is on how the linked article does not find a true signal, basically they use a process that amounts to removing high frequency information, removing low frequency information, then looking for a middle frequency signal.
The blog post points out that applying this process will produce a 'result' when asked to any input by generation pure noise, applying the process as described in the paper, then showing that the signal is now present.
Finally, the DeVries cycle is a mostly theoretical solar cycle of length 210 years, and I'm not sure what you are saying with your second paragraph.