Not P but DFW: by way of sheer ontology

[Mike Jing]

The following excerpt is from David Foster Wallace's essay *Consider the
Lobster*:

To be a mass tourist, for me, is to become a pure late-date American:
alien, ignorant, greedy for something you cannot ever have, disappointed in
a way you can never admit. It is to spoil, by way of sheer ontology, the
very unspoiledness you are there to experience. It is to impose yourself on
places that in all non-economic ways would be better, realer, without you.
It is, in lines and gridlock and transaction after transaction, to confront
a dimension of yourself that is as inescapable as it is painful: As a
tourist, you become economically significant but existentially loathsome,
an insect on a dead thing.

What does "by way of sheer ontology" mean here?