When someone describes something loosely, either due to a lack of more descriptive vernacular, or more commonly, they are being vague because they are afraid to confront a person or situation with how they actually feel. People are sometimes ambiguous because their true opinion is brash, rare, too personal, and they either simply haven't the confidence to share it, or sharing it would result in Too Much Information which could prove damaging for either party in the conversation. Ambiguity is common today in things like status messages and news headlines where the writer wants to paint a topic with a broad brush. Politicians are often ambiguous on talking points that they may wish to later flip-flop on.
i.e. status message: "I strongly dislike arrogant people", denotes a value that could use some elaboration, but would probably be too divisive or damaging to share, and so it is purposefully ambiguous.
i.e. "the massage parlour bill had an ambiguous charge added to it"