Lower two graphs are predicted waveform in event of binary system coalescence. Upper waveform left and right are observed events at each LIGO facility.

Consider furthermore that the event was observed at each facility with the appropriate lightspeed time offset, and that the wave directionality of the event was lateral and not radial from the center of the earth or some other point as would be expected from a "geophysical" cause.

Furthermore I find it highly unlikely that multiple theoretical and applied physicists would come to apparently total agreement on the significance of these findings and simply overlook the gaping logical fallacy you imply.