Yes that was the advice back in the day. But Classic inside out FHs can't be compared to Modern inside out FHs. After all there is a reason that the Pros go to this shot day in and day out. It is a critical part of the Modern game. The OP just needs to learn to hit it better against lefties.
But of course, a weak i/o shot can be a disaster if you cannot win the point within the next 2 shots, and the opponent can counter you with a dtl shot. When I play a good defensive player I would only pull and i/o if i totally have the upper hand in that point.