I am actually surprised that this is what you were taught. Consider yourself blessed. Typically RCIA programs (including the one I went through) teach the "fullness of the Truth" mantra rather than the Outside the Church There is No Salvation doctrine. The former isn't as offensive to non-Catholic ears. Never was I taught I *had* to be Catholic. Only now am I actually learning the Traditional Faith as it was taught prior to VII.
I reached my conclusions about Catholicism before I even heard of RCIA, although my RCIA class was taught by a crusty old US Marine colonel who entered the priesthood after he retired so the instruction was for the most part doctrinally sound.