The argument is that the church as a corporate structure (the church you go to is registered as a corporation) has one task and that is to preach the Gospel. Acts of mercy and care for humans (welfare) is the job of individual Christians in their daily life.
A pertinent point was made by a former President of the Missouri Synod. Writing back in the 70’s and addressing the chaos in the church as well as the chaos in the social structures around the world, Oliver Harms said, “God makes His justice be a servant. When God puts His creatures in their place even by acts of violence, then He seeks to preserve the created world as a place of reason and order and civilization. When God brings His creatures to their knees His ultimate purpose is to make them sons of grace not slaves of fear. God spares nations, and He nurtures His church because He seeks the welfare of all that He brought into being. No one portrays better the yearning of God than John the Baptist, who came to prepare the church and the world for the coming of Christ. It is from this vantage point that the church views the international strife in Indochina and the Middle East as well as the noise that occurs when God shakes the earth through quakes, tidal waves, hurricanes, and tornadoes. The church does not do enough when it simply supports the Red Cross and relief efforts for Nigeria and Pakistan. The church is not faithful if it does no more than call attention to Christ’s final return at the appropriate time in the church calendar.” It is more than an implication, it is stated as a fact that God gives His gifts to the church; nurtures the church; feeds the church so that it will help supply the needs of others for their welfare ( emphasis mine).
 Oliver Harms, “Repentance” and editorial written in Concordia Theological Monthly March 1971, Vol XLII Number 3