[KJ o]

Exactly. If you play less than 1/3 BB can always fold anything and still come out ahead! And if either you or your opponent has less than 10BB any action shold usually be a push.

If BB doesn't defend enough, always pushing is easily correct. And defending enough means calling more than half the hands, including with crap such as T7s. (Of course, if you have T7s in the BB and SB pushes, you should only call if SB does indeed push enough.)

One can actually argue that if a HU with shallow stacks last more than 6-7 hands, one or both players play poorly.