Are you sure? In England alone about one quarter of the Christians there do not believe in the resurrection:
A quarter of Christians do not believe in the resurrection
Then they are not Christians.
I think one thing a lot of people don't understand about Christianity is that a lot of people label themselves as being Christian without actually being Christian. I think people do this with being Jewish too.
Some reasons I have seen are:
1) They are not pagans.
Some people think anyone who isn't actively anti-religion/of another religion such as Hindusim and says they believe in God, label themselves as Christian on forms asking for their religion. This is often the only time they even give it a passing thought.
2) It's the family religion/tradition.
In this case, their parents are Christian or label themselves as Christian (since this can be multi generational) They probably got christened as infants, they may have gone to Sunday School or gone to church as children. They grow up thinking this makes them a Christian.
The Uk, in particular, has this kind of thinking so that article does not surprise me. They are mostly either Catholic or Anglican. If asked they will say they are X but they 'don't actively practice' or they are 'active' which means they go to church because that is what you do. They have then done their weekly 'duty'.
My own family was a bit like this. We were 'Anglican' like a badge you pass down.
I think there is a lot less of this form of 'Christianity' now because young people are less inclined to follow family tradition. When I was a child the kids who were non-religious at school had to stay out in the hall during RE and they were seen as being rather odd and something to be whispered about.
3) It's their own form.
This is where people have some form of religion and they add what they like and toss the rest. Maybe it's based around a church that they like the worship or teachings at. Oftentimes it can be a mish-mash of Christianity and any other religion/s you can name.
Jesus is often seen as a great teacher, but just one of many.