But he says "viral particles" which is a term of art and means an assembled shell (envelope for enveloped viruses like corona). If there is viral RNA in the viral particle, its an assembled shell and thus a virus. Sure some people make viral particles in the lab to package other things, but that's certainly not what OP is referring to.

Sorry, I could have been clearer and said something like RNA fragments (non-infectious residue of the virus). It's true that in a clinical situation, you need to treat the positive PCR as infectious until proven otherwise. But from a research standpoint, it seems possible that someone who previously had a high viral load in their lungs, and is now recovering, could have detectable Sars-Cov2 RNA fragments for a period of time despite the presence of endogenous RNAse. And they might not be contagious.