Well, intuition doesn't always work. The reason for removing the ground plane is simple. Any capacitance at the inverting node (summing junction) of an op amp creates peaking in the high frequency response which must be compensated by a cap across the feedback resistor, which reduces the available bandwidth. If you have a Spice simulator you can easily demonstrate that by adding a few tens picofarads (the higher the circuit resistances, the greater the effect) to the summing junction in an inverting op amp configuration.
Thus, if you want maximum bandwidth, you want to minimize anything that creates capacitance at this node, including the ground plane. Any components connected to the summing junction should be placed as close as possible to the summing junction, with short trances, and no ground plane under the op amp inverting pin any trances to that pin and any component ends connected to the summing junction.
The small inductance increase in the short traces at the summing junction due to removal of the ground plane will have little effect on the op amp performance at the usually op amp frequencies.
Now, if you are not interested in maximum bandwidth from the op amp circuit, then there may be valid reasons to maintain the ground plane, (shielding, crosstalk, etc.).