I think that he, Glazier, is correct. The concept that Jupiter acts as a shield is only partially true. Jupiter’s mass does cause objects to be deflected but there are four possibilities:
1. Object is deflected away from the inner solar system (shield).
2. Object is deflected toward the inner solar system (sniper).
3. Object falls into Jupiter’s gravity well and becomes part of Jupiter or the Jovian system (capture, a subset of shield).
4. Object passes far from Jupiter and is relatively unaffected by Jupiter’s mass.
I wholeheartedly agree. And in choice 2, once an object enters the inner Solar System due to Jupiter's having altered its trajectory, it will spend the rest of its existence orbiting the Sun, unless it falls into the Sun's gravity well. IOW, this could be the origin for some of the Earth-crossing asteroids.