Colpitts oscillator (app.note)

Hi. At this app note of microchip i saw in page 9 a colpitts configuration that i dont understand. It says:

"the crystal grounds the gate at the series resonant frequency of the crystal, permitting the loop to have sufficient gain to sustain oscillations at that frequency only."

If it is bypassing the gate at series resonance, it should be working as a CB colpitts but the feedback doesnt make sense for me. Following the figure, the crystal should be working as an inductante for oscillating, isnt it?

I agree.
Frank