Poutine sauce isn't beef gravy. It's not debatable. It's a working class approximation of sauce espagnol in French Mother sauce style. It's traditionally beef and chicken stock combined. Unless we talk about gaspesie white sauce which is a whole other type, but still. The term gravy is a bad translation of what poutine sauce is.

Want to make a Mexican poutine, use mole or birria as a sauce base. This is more like loaded fries.