For a simple virus, you certainly don't need a health care provider.
It's if the stools go on for a long time-- like more than two or three weeks-- that you might want to consult with somebody. Rarely, a child acquires a parasitic infection, for example, and the sign is loose stools that don't resolve on their own. Or the loose stools are the earliest sign of some chronic medical problem-- like Crohn's disease, or celiac, or something like that-- and the way you know is that the loose stools don't resolve after a few weeks.
That's why I'd consult a HCP if diarrhea persisted.
But if you're having them yourself-- that's almost certainly viral. And you're right, you don't need a doctor for that!