Not really. Not in today's French, anyway. "On" has taken the place of "nous" in every day spoken French. But then again, we sometimes use "we" to mean "one." Where do we buy bread? and Where does one buy bread? mean roughly the same thing: You want to buy bread, and you want to know where to go.
What is grammatically correct in one language is not necessarily correct in another.
If we are trying to break down a latin phrase, we have to translate each piece to its equivalent in english.
When we do that, we don't care about what is correct in english.
We're just trying to understand what the latin is actually saying.
where can you buy bread = where is bread available right now?/ which bakery has not run out of bread?/ what is the location of some bread currently?
where do you buy bread = what is a building/establishment that normally sells bread?/ where is bread made for exchange to the public for money?