Even atheism can mean different things to different people. In the Ancient Roman world of numerous deities the first Christians were considered atheists because they refused to acknowledge any god but their own. So if you apply their thinking to Thedas then Andraste was an atheist because she refused to acknowledge any god but the Maker.
In Ancient Greece there were those who refused to acknowledge the gods and I seem to recall wound up dead because they were seen as a threat either because they might offend the gods or because they might provoke civil unrest.
Among the Ancient Celts there were numerous tribes and feuds. However, a druid holy man could walk between two opposing armies and stop the fighting.
Religion can be a unifying thing. What enabled Maferath and Andraste to unite the numerous barbarian tribes into one cohesive whole was partly their common enemy but what kept it together was their belief in her relationship to a god. It is noticeable that after her death, the tribes would appear to have gone their own way even though many retained a belief in the Maker. No doubt this is what Drakon saw and exploited by tying his religion to his empire. Even when Orlais no longer ruled over them, the people retained their beliefs, except where superseded by another faith, the Qun.
Like it or not the majority of people in Thedas believe in the Maker. They may only pay lip service to the teachings of the Chant of Light but nevertheless it is something that unifies them. You may not like being linked to that religion but it will make your task much easier than if you try and tear it down for everyone. If you keep saying there is no Maker, people are likely to think you are working for the Elder One. That said, you don't have to accept the title they give you but without insulting the majority belief. The Creators, the Ancestors and whatever the Vashoth believe in, had to be created by something, so acknowledging the Maker as responsible for creation does not necessarily negate these religions. So personally I'll just go with Sebastian and say that until proven otherwise, when I talk about the Maker and the Creators I am referring to the same divine force or aspects of it.