Roosevelt's foreign and domestic policy were not necessarily at odds with each other.
The main reason why Roosevelt supported imperialism was because this was good for the economy. It allowed the United States to have access to the natural resources of many places all over the world. He also believed that imperialism brought some benefits to the conquered nations.
On the other hand, Roosevelt did not think that monopolies brought any benefit to the economy. Instead, the practice of monopolies harmed the economy by making it impossible for businesses to compete.
Therefore, Roosevelt was generally interested in improving and protecting the economy of the United States. This was accomplished both through the promotion of imperialism and the regulation of monopolies.
It was used to encourage support for Hitler by promoting racism.
