Is the consensus then, with the exception of avoiding a tag, to alter the basepath as-needed to avoid contact with defensemen, regardless of whether or not they're fielding a batted ball? I have to admit i'm kind of surprised. I imagine this isn't how it would be taught at the higher levels of the game so I would expect the concept of obstruction, including using it to your advantage, could be introduced at 10U.
If the defensive player is fielding a batted ball, the runner needs to avoid the fielder. Otherwise, there is no requirement for the runner to go around the fielder. That said, mowing over a fielder is not okay.
On our 12U TB team, if there is a fielder in the way of their running path (not fielding a batted ball), bumping into the fielder with a loud, "Hey, get out of the way!" is just fine. We see this very commonly at 1B with F3 standing on the inside corner of the bag