Learmonth was pretty close to the diversion point and it has a 3000m runway. However is literally in the middle of no where. Good luck if you need medical attention for PAX, and then there's the whole hassle of getting engineering support to such a remote location. Unless you need to get the aircraft on the ground right now, Perth is a better option.
However, single engine in a twin is a land at nearest suitable situation, and with no catastrophic event PAX injurys are likely to be non existent. I'm not saying they made the wrong decision, but had it being my aircraft the Learmonth decision would have being heavily considered.