Why British trade geography favored containing Japan in the Pacific

Why did Britain appear to show less interest in Pacific trade before the war?

British merchant traffic was concentrated elsewhere, so the Pacific offered a comparatively favorable place to contain Japan without exposing Britain's principal trade routes.

British merchant routes differed from the heavier American and Japanese traffic crossing the Pacific. Most British trade with North America ran to the east coast, while the empire's denser routes lay through the Atlantic and Indian Ocean. In a war focused only on Japan, a strong fleet at Singapore could try to contain Japanese naval power on the far side of Britain's main commercial arteries. Shipping geography shaped the Singapore strategy alongside fleet strength.