I think it's safe to assume that it's a toy problem. A simple example. Picking apart the example is a poor counterargument. It might be difficult to imagine a s

I think it's safe to assume that it's a toy problem. A simple example. Picking apart the example is a poor counterargument. It might be difficult to imagine a specific trivial example, but expressing a convincing example concretely can itself be a major diversion. Unless you're saying you can guarantee that your alternative is always better in all conceivable cases? Similarly, the existence of others wanting different behavior is also a poor counterargument. The fact that someone wants a Bag doesn't mean that someone else is wrong for wanting an Ordered Set.