Why would you be on a Brewers website owned by a Twins fan?
In my opinion the fandom of person owning the website or writing an article does not make their work with regard to the Brewers illegitimate.
With regard to the topic at hand, while I never pitched professionally, I was a pitcher in several amateur leagues (both youth and over 18). I had one catcher who was squirrely as hell behind the plate. It was very distracting to my concentration and accuracy. I can totally see how Contreras' pre-pitch movements could cause issues for a pitcher.
Personally, I'd like to go back to the days of getting one in ear hole if you were flashing signs from 2B.