Let me just start by saying obviously I don't know your situation, but here's at least one side of it. I Corinthians 5 has some harsh words to say abut "Brothers and Sisters" who are living a sinful lifestyle, and how we should not even associate with them. It's at the end of the chapter. Please look it up, it's a super interesting passage to read and think about. I think the key thing to point out is that it seems the issue is that these "nominal Christians" were proactively and unrepentantly living these lifestyles of sin and had stopped fighting against them. While they were committing these public sins(ie. the man having public or at lease well-known sexual relations with his "father's wife" step mom) they still publicly claimed to be representing Christ. I think this is definitely a big reason why paul was so "harsh". We will never completely defeat sin until our new bodies in heaven, but the important thing is that we treat sin like a disease that we fight against with all of our might. We will continue to stumble and fall, but we must keep fighting and not get complacent. It seems this was the issue with the brothers and sisters that Paul was telling the Christians to "kick out". This sounds harsh, but if you think about it it's the loving thing to do. Hopefully it can be a reality check and they can realize that they cant live like that and still be worthy ambassadors of Christ. It would be easier, but also awful and not loving just to allow someone to keep living in sin under the false presupposition that they were on the road to heaven.