"Two wrongs don't make a right." True, and forgotten far too often.
However, defending yourself or your property from those who seek to attack or steal is not ever "wrong". No matter who those attackers are, or what justifications they may grasp at. It may not be smart- depending on the situation- and you may not be able to do it without "collateral damage" [sic] which is NEVER right (no matter what certain thugs may claim), but defense against a thief or aggressor is not wrong. It doesn't figure into the "Two wrongs don't make a right" equation at all, but is a separate thing altogether. Don't let anyone fool you by claiming otherwise.