These aren't regular citizens, though. They're criminals. And in this case, apparently the guy was still one. I understand that many get out of jail and don't go back to what they did before, but I think that the issue isn't the fault of the police for not being armed so much as it's the fault of the criminals for wearing the body armor which protected them. The police were in the right, they just didn't have the right weapons for the job and hopefully they do now.
They should have been ready, (blah, blah, blah) but they weren't, and I'm sure that's not the first time that someone hasn't been ready for people to do something illegal. The fact they were smart enough to go get weapons from the gun shops proves they are at least able to understand what was going on; now they probably have them available.