Most religiosity is harmless, occasionally even benign. Often it's a channel for people to structure their own innate goodness around.

But ultimately it's a crutch. It gives people an excuse not to make their own moral decisions. Right and wrong is no longer reasoned as an advanced civilised being but given: handed down either by priest or by "holy" scripture.

This can be OK most of the time. Some would argue that it is the basis of all morality - thou shalt not kill etc. Without it civilisation would simply fall apart as our "base" instincts take over and we would all be too busy stealing each other's possessions, murdering each other and fornicating to make any progress. All fine except that there's no evidence to show that those with religion are any less crime prone than those without. In fact in some cases the opposite can be the case- and this is because of religion, not in spite of it.

When the people Ronald Reagan once described as "freedom fighters" flew two aeroplanes into buildings containing 5000 people they believed they were serving their God by doing so.

Look at the great holocausts of the last two centuries - the murders of 6 million Jews by European Christians, the systematic slaughter of the indigineous peoples of both South and North America, the massacre of Christian Armenians by Moslem Turks, the ethnic cleansing in Bosnia and Croatia and of course the ethnic cleansing of Palestine.

In all of these the root cause is economic rather than religious. But it is the religious dimension which allowed the suspension of morality necessary for the killing to take place. You simply turn the victims into godless savages, the infidel etc and they become fair game. It's the god delusion that made all these evils possible