I have to side with the UPCI on this one. I like how they express it on their website:
The Importance of Water Baptism
Christian water baptism is an ordinance instituted by Jesus Christ. If it is not important in the plan of God, why did Jesus command it in Matthew 28:19? And why did Peter follow up by saying, "Be baptized every one of you," and by commanding the Gentiles to be baptized (Acts 2:38; 10:48)? We must remember two points about the importance of water baptism. First, whatever Christ definitely established and ordained cannot be unimportant, whether we understand its significance or not. Second, Christ and the apostles showed the importance of this ordinance by observing it. Jesus walked many miles to be baptized, though He was without sin, saying, "For thus it becometh us to fulfill all righteousness" (See Matthew 3:13-16.)
It is true that water itself does not contain any saving virtue, but God has chosen to include it in His plan of salvation. Peter explained, "Baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God) by the resurrection of Jesus Christ" (I Peter 3:21). According to Luke 7:30, "the Pharisees and lawyers rejected the counsel of God against themselves, being not baptized."
While water doesn't contain any saving virtue...failure or refusal to be baptized underscores a complete misunderstanding of Scripture and/or outright rebellion against something Christ himself commanded. Both will land one in Hell.
If we allow anyone to compromise the necessity of baptism what's next?
Many Trinitarian denominations teach that baptism is a necessity:
Church of Christ
Orthodox
Catholic
...and many many others. I don't see them compromising. Why are we?
Baptism is a command to be obeyed. I sincerely believe that those who teach otherwise are in grave error though they may be good people.
Faith without works is dead. Those who believe that baptism isn't a necessity (a command taught in Scripture) may need spiritual CPR.