What do you do when the indifferent are indifferent to YOUR concerns? One can only pray for them. Forcing yourself on them or nagging won't break the walls their indifference.
The first thing we must do is see them as individuals, not as a group. No one ever said evangelism would be easy or the effects immediate.
I used to share your opinion on the anti-Catholics and that provoked me to anger and sin. Now I simply feel sorry for them. If their positions are based upon ignorance of the Truth or minds shaped by the way they were raised then kindness, not aggression will eventually change their hearts. If they are motivated by hatred then they are harmed by their words far more than we and they are in need of our prayers.
If we are only kind to those who are kind to us then we are exercising an indirect form of egotism. Where the Holy Spirit is you will find the fruit of the Spirit which is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control. If we are not exhibiting these we should ask ourselves why and reassess ourselves>
You have heard that it was said, YOU SHALL LOVE YOUR NEIGHBOR and hate your enemy. But I say to you, love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven; for He causes His sun to rise on the evil and the good, and sends rain on the righteous and the unrighteous. For if you love those who love you, what reward do you have? Do not even the tax collectors do the same? If you greet only your brothers, what more are you doing than others? Do not even the Gentiles do the same? Therefore you are to be perfect, as your heavenly Father is perfect." - Matthew 5:43-48