The point, for me, is never to identify whether someone is Christian. The word didn't come into popular use until Antioch, apparently, and the earliest Christians didn't call themselves Christians. If you have to be Christian to get into heaven, they're all in hell, because when they got to heaven and God asked if they were Christian, the word hadn't been used yet.
If a person says they're Christian, that's enough for me. It's not what their salvation is based on and is, at best, good for demographic purposes. Religious affiliation means almost nothing.
So these Christians might be lukewarm, faithful, African, apostate, bigoted, nearly perfect, violent, loving, very sinful, less sinful, Australian, lying, or Dutch - and how fortunate it is that we have these adjectives - but none of this makes them a Christian or not a Christian. It's the wrong question.
Anybody who looks at WBC sees. It doesn't need to be categorized and we don't need to worry about their religious affiliation. They say they're Christian. What are the other adjectives?