For Christians/religious people: Would you try to convert someone if they were Atheist or Satanist? Or a Witch? Would it bother you that much? Could you still be friends even if you disagreed?
I myself am an Athiest. I have never forced my belief on anyone and even if i was a believer and had friends like me i could not force my views on them. They are who they choose to be.
Leave them alone...that just insures one more place in Heaven for you! LOL
Seriously, you assume they are lost or confused because they have differing opinions on religion. Maybe they have found what they are looking for and it meets their needs. I think it is arrogant to feel you need to convert someone to what you believe. If you do not like what they do, and it is not illegal, leave them alone.
Never.
There are some things that are better left alone.
I could be friends with someone that I disagreed with, but not on this issue. Friends have to have some things in common and if the biggest thing in my life was sneered at by a satanist, I just couldn't be friends with them.
Love them, yes. Like them, no.