What Synastry Compares
A natal aspect is one person arguing with themselves. A synastry contact is one person's planet falling on another's, and it describes what happens between them rather than inside either. The Moon of one landing on the Venus of the other is not a fact about either character; it is a fact about how those two behave in the same room. This is why a chart that looks difficult alone can be easy alongside somebody, and why two straightforward people can be impossible together.