Working with RF Amplifiers for the first time
Because it's not a standard op-amp. 

It's basically an output device, with a bit of bias to keep it happy, which drives straight into the output line. There's no negative power supply as it's been designed to be used without.

For efficiency, the high current required is supplied through an external inductor. There's no way an inductor of the required size could be placed on chip.

With specified operation to 1GHz, and gain well beyond that, you'd better follow the data sheet recommendations exactly, unless you know exactly what you're doing.