Critical point here. Having "no fellowship" does not obviate the command to love my neighbor, even my heretical and heathen neighbor. It is no great thing to love folks who are just like me. It's easy.
Loving that nasty _________ (inset most despised person / group) - there is the hard stuff. The impossible that is demanded.
According to Calvinist theology, many heathens and heretics are future denizens of the Kingdom of God, having been chosen from the beginning of time (but just not having been called yet). So the heathen or heretic you shun today may in fact be one of the elect. Nice going.
There is ONLY one cure for that and that is to pray for that person/group evertime their name enters your mind...sometimes it takes weeks, sometimes days, and sometimes satan knows you mean it and leaves after a couple of tries..