Break it down as you see it, CM.
I already did above. The addition of the words "just as if by this very fact," are the words by which his entire statement is qualified. Read over my explanation again. Believe me, I spent a lot of time mulling this one over because of the
apparent contradiction between this and Florence.
Don, the theological opinion of limbo without fire is contrary to the dogmas of Florence, unless one makes one of the following assertions (by which one would fall into heresy anyway):
1) Unbaptized infants are inside the Church.
2) Those dogmas do not have to be understood as they were declared, but only in historical context.
The first is contrary to all kinds of dogmas, and the second denies that these dogmas are infallible, irreformable truths which haven fallen from heaven.
Just because a proposition which is contrary to a dogma has not been formally condemned by name doesn't mean that we can hold to it, or that it is not heretical. A dogma is a Divine and absolute truth. To contradict it in any way is to be heretical.