From the article

But not all agriculture is equally land-intensive. Meat-heavy diets require far more land than low-meat and vegetarian diets.

But not only that it also requires crop land for plant-based diets. From a different source

If everyone shifted to a plant-based diet we would reduce global land use for agriculture by 75%.

[…]

If we would shift towards a more plant-based diet we don’t only need less agricultural land overall, we also need less cropland.

https://ourworldindata.org/land-use-diets