I also get very annoyed by people doing straight-in approaches at uncontrolled airfields; especially when they aren't aware that they have to give way to circuit traffic, or claim not to have seen anyone on base leg.
An OHJ is certainly the default, but I don't know why more people don't get taught about IP joins. If approaching in the runway direction it's so easy to arrange to fly just to the deadside of the runway and then to turn onto downwind at an appropriate point (usually over the upwind numbers). It also helps with descent and energy management so why isn't it in the standard text books?
HFD