Exactly, while it's more conventional to have black holes at the SS, 2B, or C positions, if you have better players at those positions then it's acceptable to have a black hole at 3B. In other words, it's better to look at black holes relative to the lineup itself rather than looking at black holes relative to the positions that they play. 3B is usually seen as a power bat position, but if you have no other blackholes and a good fielding 3B, then the 3B can hit like a blindfolded Julio Lugo and the team should be fine, depending on their pitching, fielding, coaching etc.
Also, I am aware that a blindfolded Julio Lugo might indeed hit better than a regular Julio Lugo, but for the purposes of the analogy let's assume that it'd somehow make him worse.