Forgive me, I thought that we baptized whenever it was needed, not just during two seasons of the year.  How did I miss this, in all of these years of being Catholic?

Why would Pope St. Leo teach in a letter directly addressing the topic of Catechumens and baptism that there is only one "safeguard of true salvation"? Even describing how the ways claimed by adherents of BOD and BOB, which to them, would somehow provide the effects of baptism without actually receiving it, still only have one single safeguard... Namely, baptism with true and natural water. If there is anywhere where BOD or BOB should be have been taught if it truly was the doctrine of the Church, it would be in this letter from Pope St. Leo, yet we only find the contrary...

Very good video on the topic for those who haven't seen it:

https://www.youtube.com/watch?v=L-y5yJTCMWg

Article 3. Whether Baptism should be deferred?
Objection 1. It seems that Baptism should be deferred. For Pope Leo says (Epist. xvi): "Two seasons," i.e. Easter and Whitsuntide, "are fixed by the Roman Pontiff for the celebration of Baptism. Wherefore we admonish your Beatitude not to add any other days to this custom." Therefore it seems that Baptism should be conferred not at once, but delayed until the aforesaid seasons.
Objection 2. Further, we read in the decrees of the Council of Agde (Can. xxxiv): "If Jews whose bad faith often "returns to the vomit," wish to submit to the Law of the Catholic Church, let them for eight months enter the porch of the church with the catechumens; and if they are found to come in good faith then at last they may deserve the grace of Baptism." Therefore men should not be baptized at once, and Baptism should be deferred for a certain fixed time.
Objection 3. Further, as we read in Isaiah 27:9, "this is all the fruit, that the sin . . . should be taken away." Now sin seems to be taken away, or at any rate lessened, if Baptism be deferred. First, because those who sin after Baptism, sin more grievously, according to Hebrews 10:29: "How much more, do you think, he deserveth worse punishments, who hath . . . esteemed the blood of the testament," i.e. Baptism, "unclean, by which he was sanctified?" Secondly, because Baptism takes away past, but not future, sins: wherefore the more it is deferred, the more sins it takes away. Therefore it seems that Baptism should be deferred for a long time.
On the contrary, It is written (Sirach 5:8): "Delay not to be converted to the Lord, and defer it not from day to day." But the perfect conversion to God is of those who are regenerated in Christ by Baptism. Therefore Baptism should not be deferred from day to day.
I answer that, In this matter we must make a distinction and see whether those who are to be baptized are children or adults. For if they be children, Baptism should not be deferred. First, because in them we do not look for better instruction or fuller conversion. Secondly, because of the danger of death, for no other remedy is available for them besides the sacrament of Baptism.
On the other hand, adults have a remedy in the mere desire for Baptism, as stated above (Article 2). And therefore Baptism should not be conferred on adults as soon as they are converted, but it should be deferred until some fixed time. First, as a safeguard to the Church, lest she be deceived through baptizing those who come to her under false pretenses, according to 1 John 4:1: "Believe not every spirit, but try the spirits, if they be of God." And those who approach Baptism are put to this test, when their faith and morals are subjected to proof for a space of time. Secondly, this is needful as being useful for those who are baptized; for they require a certain space of time in order to be fully instructed in the faith, and to be drilled in those things that pertain to the Christian mode of life. Thirdly, a certain reverence for the sacrament demands a delay whereby men are admitted to Baptism at the principal festivities, viz. of Easter and Pentecost, the result being that they receive the sacrament with greater devotion.
There are, however, two reasons for forgoing this delay. First, when those who are to be baptized appear to be perfectly instructed in the faith and ready for Baptism; thus, Philip baptized the Eunuch at once (Acts 8); and Peter, Cornelius and those who were with him (Acts 10). Secondly, by reason of sickness or some kind of danger of death. Wherefore Pope Leo says (Epist. xvi): "Those who are threatened by death, sickness, siege, persecution, or shipwreck, should be baptized at any time." Yet if a man is forestalled by death, so as to have no time to receive the sacrament, while he awaits the season appointed by the Church, he is saved, yet "so as by fire," as stated above (Article 2, Reply to Objection 2). Nevertheless he sins if he defer being baptized beyond the time appointed by the Church, except this be for an unavoidable cause and with the permission of the authorities of the Church. But even this sin, with his other sins, can be washed away by his subsequent contrition, which takes the place of Baptism, as stated above (III:66:11).
Reply to Objection 1. This decree of Pope Leo, concerning the celebration of Baptism at two seasons, is to be understood "with the exception of the danger of death" (which is always to be feared in children) as stated above.
Reply to Objection 2. This decree concerning the Jews was for a safeguard to the Church, lest they corrupt the faith of simple people, if they be not fully converted. Nevertheless, as the same passage reads further on, "if within the appointed time they are threatened with danger of sickness, they should be baptized."
Reply to Objection 3. Baptism, by the grace which it bestows, removes not only past sins, but hinders the commission of future sins. Now this is the point to be considered—that men may not sin: it is a secondary consideration that their sins be less grievous, or that their sins be washed away, according to 1 John 2:1-2: "My little children, these things I write to you, that you may not sin. But if any man sin, we have an advocate with the Father, Jesus Christ the just; and He is the propitiation for our sins."