The designer should have received all relevant context prior to starting the task. There will be exceptions, where a piece of context is missed, and in these cases where feedback is necessary the format of the feedback is important.

Rather than, "do it this way because businessReasons."

Instead, try, "We must not have properly conveyed this aspect of our business, here is the relevant context. Knowing this, how do we solve this design problem?"

If the designer is incapable of translating business requirements into design solutions then perhaps they're not a product/ux designer, maybe just a visual/graphic designer.