This idea contains a grain of truth, but is exaggerated (it's television after all.)

This was thoroughly explored in John Dower's seminal work War without Mercy which documented the dehumanizing and racist propaganda used by both sides in the Pacific war. Depictions of Japanese as primitives or animals was extremely common, and apes or monkeys in particular were a pretty commonly used image in the U.S. and British media, especially political cartoons. The government basically encouraged and directed this propaganda. The overall brutality with which the Pacific War was waged by both sides can be tied to this propaganda and it's mirror image on the Japanese side.

However, it's a pretty far cry to say that this was intended to be taken literally by civilians or military personnel and the US government was trying to convince its citizens that the Japanese were another species. If any enlisted men held this view, they would be a very small uneducated minority. Most western audiences were aware that political cartoons were intended to be viewed figuratively rather than literally. The view that the Japanese were extremely dangerous, could never be trusted, and might deserve extermination was held however, and sometimes held by surprisingly high ranking officers.

Obviously, these genocidal views were not compatible with a peaceful postwar occupation of Japan intended by US policy. Therefore there is somewhat of a U-turn in propaganda which occurred immediately after the war ended and the occupation began. This is also described in Dower's subsequent work Embracing Defeat.