I'm also currently reading Ken Costa's book God at Work. On page 43, he uses slightly different words to a phrase I've heard before. Costa writes:
As we engage with society's issues, we are called to confront anything that draws people away from God, but at the same time to comfort those who are struggling. But how often does our society end up confronting those who need comforting and comforting those who need confronting?I've head this saying before as 'afflict the comfortable and comfort the afflicted' but I think I prefer Costa's 'confront the comfortable and comfort those who need comforting', even if the phrase doesn't have the same word-play. I think Costa is absolutely right that there is something about human nature that makes us want to 'get in good' with those who are in power rather than to confront them with their wrong-doing. Similarly, the sinful part of human nature means that we are often tempted to hurt those who need help: be it on a macro-scale (e.g. rich countries exploiting poor countries) or at a one-to-one level (e.g. taking out our frustrations on someone who we perceive can't hurt us).
When we say that 'the church is too nice' do we mean that we are not challenging those who are comfortable in their wrongdoing? If so, then we need to think and pray about how we can have the courage to speak God's truth in a challenging but constructive way. By the same token, there will always be people in society and in the church who need comforting and we are most certainly called to comfort those who need it.
It's not just 'the world' that is tempted to confront those who need comforting: the Church has also fallen into this temptation and succumbing to it is probably an excellent way to serve The Enemy and to be a bad witness for Christ.
 God At Work: living every day with purpose by Ken Costa, London, Continuum Books, 2007.