It is really not a big fat lie but a small oversight.
The showAsAction attribute must be defined using a different namespace "http://schemas.android.com/apk/res-auto"
You should therefore in your top menu tag define a namespace as follows
xmlns:app="http://schemas.android.com/apk/res-auto"
and then use that to define your showAsAction attribute like so
app:showAsAction="ifRoom"
That should fix it