Why should getting baptised be encouraged?
Whether or not baptism should be encouraged is dependent upon an individual's personal beliefs. If a person comes to adopt the tenets and beliefs of one of the branches of Christianity, baptism is an important symbolic ritual and expression of that faith.
The act of baptism is directly based upon the baptism of Jesus in the Jordan River by John the Baptizer, who was the first to recognize Jesus as being the special someone sent by God whose coming he had been proclaiming. Upon coming out of the water, the spirit of God descended upon Jesus in the form of a dove according to the Gospel of Luke.
When followers of Christ are baptized, they are proclaiming their faith in God, their belief in Jesus as savior, and their desire to be united with all who believe through the act of being washed clean of sin.
Those who practice any faith that involves the rite of baptism will agree that the main reason why it should be encouraged is because baptism is a right of passage, or better yet, entrance into a group. Any rite that involves becoming an essential part of a group is indicative of the need to infuse confidence in the new member as far as ensuring that he or she will be welcome, and taken care of.
In other systems of belief, baptism refers to becoming anointed by the Holy Spirit, and therefore you are officially a part of the faith with the "blessing" of a higher power.
These are mostly the reasons why baptism is encouraged: as a rite of entrance into a common group, and as a rite of blessing in order to practice a specific faith.
If you belong to a sect that believes in adult baptism, then you would want to encourage baptism because you would want people to be saved. You would want people to get baptized because, by being baptized, you are stating that you accept Jesus Christ as your savior. You should want people to do this and so you should encourage baptism.
If you are Catholic, you believe that the baptism of an infant (or an older person for that matter) allows God to come into the person's soul. You should want that to happen because it will allow the person who is baptized to live a fuller life due to the presence of God in their soul.