He seemed to have no issue with coming to a "stained" world populated by "stained" people with whom He interacted constantly. Are you suggesting that Jesus can be contaminated by His surroundings? Is His divine nature so fragile that contamination would even be possible?
We’re not discussing “what’s possible”, we’re talking about what happened.
Angle Gabriel made it quite clear Mary was “full of grace”.
That grace was present from the moment of her conception.