You're right of course. In my defence I was armed only with Robson and a lack of experience I thought the tail would be a distinguishing feature, but there was no mention of it.
Live and learn
I actually saw an Oriental Magpie-robin on Campus here in Jiangsu. The white bars on its wings and tail were much more obvious in flight. It's a very attractive bird.
it is difficult starting out birding in the tropics because if you are only familiar with European birds you really have no idea where to even narrow your search down to in the field guide, even if you know the bird you saw is a type of passerine. Is it a robin, a bulbul, a flycatcher - who knows? It just comes with experience and time.