Who said "The real mystery is why anyone would be mean."?

This quote is attributed to Scooby-Doo.

The real mystery is why anyone would be mean. - Scooby-Doo

"The real mystery is why anyone would be mean."

Scooby-Doo Justice

"Scooby-Dooby-Doo, where are you?"

"Ruh-roh!"

"Like, zoinks!"

"Let's split up, gang!"

"Justice must always prevail."

"You think I'm just some animal?"

"Fighting for what's right never gets easier."

"Justice is worth fighting for."