17 Q. Can the absence of Baptism be supplied in any other way?
A. The absence of Baptism can be supplied by martyrdom, which is called Baptism of Blood, or by an act of perfect love of God, or of contrition, along with the desire, at least implicit, of Baptism, and this is called Baptism of Desire.
This reply is from Neil Obstat about 5 years ago:
How can the absence of something be supplied by something else?
This quote from the catechism says that martyrdom can supply the absence of baptism.
Why would anyone want to be supplied the
absence of baptism?
If you want to cook breakfast and don't have any eggs, would a shopping trip SUPPLY your absence of eggs? Or would a shopping trip REMEDY your absence of eggs?
A platoon commander running out of ammunition, when asking for supplies, would he say that he is requisitioning to be supplied an absence of bullets?
The choice of words is highly ambiguous, at least. This goes to show that catechisms are not a source of doctrinal definition. They are only a tool for teaching, and can therefore contain errors that the censors overlooked.