Patrick Henry is using a rhetorical question to emphasize the fact that if Britain loved America, they would not be sending armies and force to rule them.
In this passage, Patrick Henry is arguing against the idea that Britain is sending fleets and armies to America out of a desire for love and reconciliation. He uses rhetorical questions to challenge this idea and to suggest that the real purpose of these military forces is to subjugate and control the American colonies. By asking whether fleets and armies are necessary for a work of love and reconciliation, he is implying that they are not, and that Britain's actions are therefore not motivated by a desire for peace and harmony. This underscores the idea that the colonies are being oppressed and that force is being used to maintain British rule, rather than to achieve any kind of positive outcome.