When considering plant matter, why is incidental ingestion by wolves not evidence of omnivory?

Answer

The consumption is neither intentional nor nutritionally significant.

While trace amounts of plant material might be ingested incidentally, the wolf does not seek plants out for nutritional gaps, as its entire system is geared toward meat.

When considering plant matter, why is incidental ingestion by wolves not evidence of omnivory?
animalArcticwolfCarnivore