Your second objection is to our practice of baptism by pouring the water. We also hold as valid the practice of sprinkling, provided the water drops flow upon the skin. But Christians have always considering pouring or sprinkling to be a sufficient external sign of baptism's interior cleansing. Furthermore, the root meaning of any word does not completely correspond to its actual usage. This is baptism by infusion, not by immersion.
Baptism is necessary for salvation.
Therefore immersion cannot be the only valid method. We do not deprive prisoners, the sick, the dying, people in the desert or in the frozen North of this necessary sacrament by insisting on immersion. Just a little water will do. This is the constant teaching and practice of the Church and was never questioned until after the rise of Protestantism. And even many Protestants adhere to the ancient teaching in this regard.