You cannot defend what is not yours.

In a 1-2nl cash game the pot is $3 to begin with before the cards are dealt. You may have contributed to this pot but any chips thrown into the middle become chips of the pot and no longer chips of your own. So, do not try to defend anything, because nothing in the middle is yours.

Instead of looking at it as 'blind defense' (which it is not), look at it as taking advantage of aggressive players.