The term 'spiritual' is very popular in religious circles, precisely because of its ambiguity. Many people, like Gervais, take 'spiritual issues' to mean moral or emotional issues, but religious people are fond of taking it to mean a diluted version of religious issues. Whilst many people in the secular West may be repelled by religion, they may be more susceptible to 'spiritual issues', which is presumably why so many religious programmes on television now purport to address spiritual issues, rather than religion itself. Hook them with the spiritual issues, and then suck them into religion, seems to be the strategy.
Note also that when the Archbishop tries to suggest that forgiveness makes you a Christian, Gervais is quick to correct him, pointing out that you need forgiveness to be a Christian, but forgiveness doesn't make you a Christian. It's the difference between a sufficient and a necessary condition, a distinction with which a philosophy graduate such as Gervais will be more than familiar.
Ricky Gervais Radio 5 Archbishop of Canterbury Christian