Dialectically, this person is exactly right; existence viz the process not the quality, is the single most serious thing in all existence, possessing a self-reifying essence. In denying their seriousness, you're denying them their essence and their thing-in-of-itselfness, more or less atomizing them into a sort of ontological foam. A rhetorical equivalent of a Wellian heat ray.

Correlate that with the reinforcing and supporting nature of the relationship that the rhetorical and ideological superstructure have with the material base, such rhetorical annihilation must surely be followed by the physical equivalent.