Irritating

This post on Stumbling and Mumbling bugs me.  For a number of reasons.  First I never see why people feel the need to qualify any positive statement about religious (usually Christian) people such as "There’s some evidence that religious believers are more prosocial and more likely to give to charities" with things "" like "This doesn’t necessarily mean they are nicer than non-believers".  Why?  Why can't it just be accepted that religious people may be more social and more giving?  Dillow then compounds this with his next statement: "It might just be that the fear of eternal damnation gives them different incentives than non-believers". Again, why? Why is it casual commentators always have to peddle the picture of Christians (usually) as only acting out of fear?  We all go along to church in some masochistic manner, just waiting for that fear to be drilled into us, poor irrational buggers that we are.

Why is the true motivation for Christians doing good never put forward?  That Christians respond to the grace shown to them by God through Jesus, and hence feel obliged to respond in kind to others?