I know exactly what happened here having just done a renovation on a basement with a completely fucked up bathroom.
They re-used the existing piping and lines when replacing the tub and shower surrounds.
They wanted to save a few hundred dollars and/or effort of moving the pipes to center up with the prefab tub/surround, and just figured they could drill the hole into the surround for the shower attachments wherever.
They’re correct, but that doesn’t make them right.
Ah, that’s possibly true as well. Good catch.