Jesus was talking to his disciples and followers. Those who have been with him in his ministry and the people who may have heard about his teachings and want's to be healed from their diseases (Luke 6:17-19).
What does love mean? Is it the indifference to everyone's sinning? No! It is a self-giving love and affection that wants the enemy know Christ and be saved (John 3:16). True believers are to love his enemies.
Who are the enemies? Those who hate believers. Those who curse believers. Those who abuse believers. This is not just any kind of hate and curse and abuse. These are opposition that we receive when we became followers of Christ. So don't be deceived, true believers are being hated and cursed and abused by enemies.
By the power of the Holy Spirit who was given to us when we believed in Christ, we are able to reflect God's love to them.
All who believes in Jesus Christ are to love the enemies who hate, curse and abuse them because of their faith. By the power of the Holy Spirit who was given to us when we believed in Christ (Acts 1:8), we are able to reflect God's love to them. That is by, doing good for and to them, seeking their good first before ours, blessing them and being kind and gentle to them, praying for their change of heart that God might lead them to repentance, praying for yourself for humility that you may see their hating, cursing and abusing as a confirmation that you are in Christ.
Jesus modeled for us how to live a life as a believer facing persecutions from the people close to us. We are able to love, or should I say, forgive our enemies not as a means to be saved but as a result of God's work in our lives. He died on the cross so that we can be forgiven and release forgiveness (Mark 11:25).
Love those who hate you because a great reward is kept in heaven for you (Luke 6:22, 23). That reward is God himself and the crown of eternal life for those who believed.