Regarding the issue of arming all police officers it would be wrong as from inception, the police have not been armed. The day every officer in the UK mainland is armed policing will no longer be by consent as laid down by Robert Peel. While I'm not privy of the amount of armed police, there are more than you think.
I don't think even if the two officers were armed the outcome would have been any different as Gregan had a stock of russian made grenades which he did use on the day.
It turns out that Dale Cregan 29 was on Police bail from June, he had been charged for a pub shooting where he had gone to kneecap a gang member, but it had gone wrong when the intended victim was hit in the neck.
The system is wrong to allow a person who has been charged with a firearms offence. They should never be given bail, he should have been kept on remand until he was either cleared or sentenced for that offence.
It would seem that Facebook has again been used for offensive remarks.