This is an interesting question.
I went to the homepage of the YMCA and read their "History" pages. Good stuff, well-intentioned and upright. In part, it tells us:
"George Williams founded the YMCA in 1844.
In 1844, industrialized London was a place of great turmoil and despair. For the young men who migrated to the city from rural areas to find jobs, London offered a bleak landscape of tenement housing and dangerous influences.
Twenty-two-year-old George Williams, a farmer-turned-department store worker, was troubled by what he saw. He joined 11 friends to organize the first Young Men’s Christian Association (YMCA), a refuge of Bible study and prayer for young men seeking escape from the hazards of life on the streets.
Although an association of young men meeting around a common purpose was nothing new, the Y offered something unique for its time. The organization’s drive to meet social need in the community was compelling, and its openness to members crossed the rigid lines separating English social classes.
Years later, retired Boston sea captain Thomas Valentine Sullivan, working as a marine missionary, noticed a similar need to create a safe “home away from home” for sailors and merchants. Inspired by the stories of the Y in England, he led the formation of the first U.S. YMCA at the Old South Church in Boston on December 29, 1851..."
I note with no small amusement (i am EASILY amused) that the YMCA was well underway BEFORE Pastor Russell had his scheme hatch.
On the official YMCA website there is no statement that "The Y" is no longer a "Christian organization. I have sent them an email requesting clarification.
If they reply I will update here.