If atheism is 'true', then it is not necessary to generate 'true thoughts' about the nature of God because he/she/it does not exist. That is the only 'true thought' that is needed.

The universe is not the same as god. Unlike god the universe's existence can be proved, therefore further study of its origin, nature etc is justified. Whether it is a logical system or one which is chaotic I have no idea, but I can understand why people want to explore it. After all they do not have to waste time proving it's there to start with!