Even if he's armed the danger and actual crime committed is so insignificant there's no reason to employ the tactics they used.
Just because some force is reasonable doesn't mean all force is immediately reasonable and it's not stuck at higher levels as the situation changes. While he's being chased and posing a higher threat more force is reasonable but once he was barricaded in the house the danger posed to the public is reduced.
Surround it and wait for them to give themselves up. That's what other countries do.