Good points.
Jesus didn't criticize several Christian centurions for their occupation.
Stephen was submitting to the governing authorities in the Romans 13 sense - which also authorized them to bear the sword.
Still "Take a purse and a bag and sell your cloak for a sword" is a command to each individual being sent out into the mission field" since it follows a reference to the last time he sent them out two by two. So part of their standard missionary equipment was a way to defend themselves along the way. More important than a cloak on a cold night!