[Dylan16807]

> Why does the executive branch exist at all if it's simply to enforce written law?

Someone has to be in charge of enforcing things.

> Why do we elect the executive at all if they are merely to enforce written law?

Do you have a suggestion of another way to do it that doesn't put congress in charge?

Also the president has some other very important roles.

> Why do executives have the power to pardon someone when a court of law finds a person guilty of breaking law?

That one is definitely subjective by its nature, but also the average number of pardons is around two thousand, a very small fraction of cases.