In some ways yes, in other ways you’re way off.

D/s reflects general power dynamics. Straight couples with dominant men often use the existing gender relations for it. And dominant straight women often invert it. But plenty of other power dynamics are used here, such as elder/younger, noble/servant, boss/employee, military, teacher/student, owner/pet, etc. Hell a lot of power exchange organizations are still moving away from master/slave terminology.

And sadomasochism seems deeper in the human psyche than Christianity. Yeah Christianity really encourages it, but it seems to be more like runners high and the appreciation of horror movies than just some reflection of Christianity.

Both D/s and sm are very broad categories whereas findom and race play are both categories of D/s