When I was a kid I thought this was an artifact of an ancient culture. From the perspective of 1975, it probably was. Wikipedia:

"Caspar Milquetoast was a comic strip character created by H. T. Webster for his cartoon series The Timid SoulWebster described Caspar Milquetoast as "the man who speaks softly and gets hit with a big stick". The character's name is a deliberate misspelling of the name of a bland and fairly inoffensive food, milk toast. Milk toast, light and easy to digest, is an appropriate food for someone with a weak or "nervous" stomach.

The character's original name was Egbert Smear. Wikipedia notes: "The character was said to have ushered in a new era of timidity in comics."