“...because there is no way to test it as science.”
Yes there is. Go to a comet and take a sample, bring it back, and analyze it. Or test it in situ. Do this to a bunch of comets, publish the results.
The current concept of clay particles from comets comes directly from a visit to a comet by a spacecraft, not from an untestable hypothesis.
But nobody has ever SEEN life begin in clay. Life has never begun in laboratory clay. Life has never been seen BEGINNING from non-living substances or chemicals or compounds in any laboratory anywhere. Life has not been found by any spacecraft in any clay on any comet. What does finding clay on a comet prove. That a comet might carry clay. That’s it. zip.