Waze rep here, the “aggressive routing” is due to the No Turn On Red restriction at the light at Cold Spring/Harford. You could lift that restriction, at the peril of pedestrians (hint: don’t do this) and solve the problem. You could also (and should) make List Ave one way eastbound and put a No Left Turn restriction at the east end, effectively negating the usefulness of the cut through. The barrier option could have unintended consequences like impacts to emergency vehicles (and it looks low budget.)