Sorry I missed this argument, I was travelling on a business errand and it must have slipped through my awareness!
He clearly adopts the penultimate archetypical stereotype caricature of the "atheistic sceptic", leading to him being an effective battlefield commander. In many ways the Jedi and Sith are two sides of the same coin, both fanatically religious with warring ideologies, totally rigid and unwilling to compromise with one another, while the Jedi may seem more "reasonable", they are equally rigid to the Sith in their devotion to the Force and their principles, some might say to a fault.
Whereas the Dark Jedi does not hold such beliefs sacred, they are typically characters with human faults, conflicting world views and ideas a traumatic past. Their viewpoints are not so much informed by institutional indoctrination or some would say religion, but by their real world experience and troubles. In this way a Jedi would find it hard to relate to their Dark Jedi cousins who are not as "indoctrinated in religion" as them.
Thrawn being a cold sceptic fits this mould, while he clearly has an Imperialstic leaning and outlook, he is also not bound by dogma of any kind and would rather use logic, reason and experience to further his ends, much in the same way the Dark Jedi have differing motivations from the Jedi but still ally WITH THEM, Thrawn is something of a Gray Sith or what used to be known in the classical EU as a "Dark Jedi" - indeed the Sith once were called "Dark Jedi" but as more and more complexity was injected into the EU universe, this simplistic view of dark and light was overshadowed, pardon the pun, by a more nuanced and sceptical viewpoint, very much leading into this concept of the enlightenment and death of god we have experienced in real world history.