If there are files under `exportDir` that don't contain valid resource yaml, the user will see a low-level error message that doesn't indicate what the CLI was trying to do or why it failed. For example, one possible error the user might see is:
```
Error: Object 'Kind' is missing in 'null'
```
This sort of message does nothing to tell the user that there's a problem in the files found in the export directory.