why not use kubectl diff?

[dudicoco]

https://github.com/argoproj/gitops-engine/blob/master/pkg/diff/diff.go states the following:

The package provide functions that allows to compare set of Kubernetes resources using the logic equivalent to
`kubectl diff`.

Why is it necessary to maintain this code if the logic is equivalent to kubectl diff? Why not use kubectl diff instead?

[caozhuozi]

same question here