> I'm not sure why Presidents were given the ability to pardon.

Won’t somebody please think of the ~~children~~ turkeys?!

https://en.wikipedia.org/wiki/National_Thanksgiving_Turkey_P...

Joking aside, Wikipedia does have a history of it. It goes way back, way before the USA was even a thing.

https://en.wikipedia.org/wiki/Federal_pardons_in_the_United_...