From what I understand, being someone who runs in Christian circles, the basic idea of "love languages" wasn't ever really intended to be some sort of final word or taken as hard science as the author of this article seems to think. Instead, it's meant to be a useful way of looking at things to help people understand their partners and their own needs better and how to communicate with them. You could probably still call it pseudoscience with the way some people treat it but I don't see how it's fair to implicate the writer of the five love languages as being a conman cause it probably was never really intended to be science in the first place.
That being said, I haven't actually read the book for myself, only having heard him on radio interviews and elsewhere, and I haven't thoroughly read this article, so it's entirely possible I'm just missing something. I also agree that calling him "Dr." without clarification is misleading.