Perhaps you were dealing with either an unexperienced parts guy or one who went for a quick answer.

I've been really deep into these things over the years. When you get into wiring bits you have to know what you're doing and use some thinking outside of the parts catalog. Wire terminals are really easy to look up right up until they aren't easy. I frequently find myself having to switch car models to find what I need.

Most parts guys don't realize they have access to the technical wiring diagrams and the majority of those who do have no idea how to use it.