The biblical concept of “holiness” is not simply “doing good”, but it is the context that defines what is good and infuses our doing good with divine significance. The relationship between holiness and what the world sees as “good” is complex: sometimes they coincide, sometimes they are askew, and sometimes they come directly into conflict.
Inasmuch as non-Christians do good, they are working with Christians in doing the will of the Lord Jesus. Non-Christian goodness does not supplant or negate the lordship of Christ. It confirms and demonstrates it.
The relevance of the Church is not dependent on its ability to strategically adjust its message to pertain to what the world is concerned about. Rather, the Church only needs to concern itself with being relevant to ground of all reality, God himself in Christ. Inasmuch as it does this, what the Church has to say is by definition the most relevant thing that can be said.