It's difficult not to agree with you. However, as a Christian and a Church member, I know that most families who come to church regularly will be involved in activities to do with the church, its upkeep, social activities, help in the community (food bank, night shelter, visits to the elderly, etc) and yes, I know it's taboo nowadays, but will give money to the church. Our church is linked to a primary school and some families just come to church once a month and to hope and get their child in the school, and do not participate in church life at all. But the school is so oversubscribed (over 150 applicants for 30 places) that only families who come more often will get in (except looked after children). Then it's in order of catchment.
And yes, the church is working very hard to have many services, one on Saturday evening, two on Sunday morning, most with nursery church and Sunday school, and twice during weekdays, to try and accommodate working parents, those working shifts etc.
And yes it is mostly middle class, but our local area is middle class.
And no, it's not overwhelmingly white, I think it's 26% either mixed race or of other ethnic groups. Most have English as a first language but that's also representative of our local community.
I think that the article is superficial, and doesn't give enough details. THe example of flower arranging is petty. They could have mentioned any other work in the community.