I'm not sure that going to church for social reasons means someone is politically Christian.
Those such as the American Evangelists are, but people, especially some older people in this country particularly, may just go for social reasons, for interaction with others, to combat loneliness and indeed because they do want to help others in practical ways eg running food banks.
Owever, I do think most of those who do attend regularly have a deep faith. I know several people who do, C of E, RC, Methodist etc but would have no clue as to their politics which, imo, is entirely different and varies from person to person.
Of course, Jesus himself was very political!