Sending police out armed with firearms will only induce gangs to purchase more weapons of their own in response and increase the likelihood of gunfire exchange with whole communities caught in the middle. The only way people can be made to feel safer is for there to be fewer guns on the street, not more.
People do not feel reassured seeing armed police, instead feeling less safe, so the counterpoint falls down. Because we are usef to the police not having guns armed police make us feel less safe. If your community has armed police then obviously something very bad is happening!