To be fair, most derailleur hangers can get bent.I'm afraid this illustrates the hidden cost of budget Chinese bikes, fittings, bolts and the like are often made of cheese, so when it comes to laying an allen key on them, the mechanic is never sure what will happen next.
His has got bent probably when the chain jumped and got entangled or the freewheel got jammed.
http://www.ribblecycles.co.uk/blog/gear-hangers-break/Gear hangers, or replaceable dropouts as they are otherwise known, are designed to be replaceable. They are usually made of alloy and will break under extreme stress in order to save your frame from being damaged. This can be the result of a crash, mis-shift or most usually simply being in the wrong gear when the chain and derailleur are under the most load either when the road goes upwards sharply or setting off from a standing/stationary start.