YMCA stands for the Young Men's Christian Association. This was an all male association. The women and girls had their own, called the YWCA; Young Women's Christian Association. It was one of the early health clubs, where anyone was welcome to come and play sports; basketball, run on their indoor track, exercise with weights, and pulley machines, and swim in their pool. I learned to swim there. It also would accommodate older men/women who were down on their luck, with a place to stay overnight and/or get a hot shower for cheap; promote the general welfare through charity.
This was before Liberalism and women's liberation forbidding separate sex facilities, and before trans men were allowed in women's locker rooms. Gay was also not yet liberated, but stayed in the closet; don't ask and don't tell. They had to perv clandestinely. Now it is more family oriented with separate locker rooms. Liberalism has distorted former reality to where what was normal back then; male and female polarization, is now perverted and this perverted is their new norm; revisionist history.
In terms of Trump, he is smart since he is stealing even gay and lesbian votes from the Democrats. It is likable song, that easy to remember and can be interpreted in many ways but gives off a good vibe of unity.