it's difficult to distinguish between things when you have limited information or knowledge.
The phrase is often used to describe situations where:
* People are judged based on superficial qualities: You might say "All politicians look the same in the dark" to suggest that people don't pay enough attention to individual policies and focus too much on stereotypes.
* It's hard to make a clear decision: You might say "All these job offers look the same in the dark" when you're struggling to choose between similar opportunities.
* Details are obscured: You might say "All the houses on this street look the same in the dark" when you're trying to find a particular address.
The idiom emphasizes that lack of clarity can lead to inaccurate judgments and confusion.