This rarely seemes to be an issue with other foreign made products like Microsoft, Apple, Amazon etc. I would've thought that one would want all critical infrastructure to be made in country.
I understand what you're saying, I've just not seen one with any indication of a wave stirrer. They all just shoot the beams from the magnetron through a ceramic plate on the side if the microwave. The top interior of the microwaves I've used (even one ones from Samsung and LG) had no holes or vents. Maybe it's just an American thing?
The diagrams I've seen show the wave stirrer on the roof. The microwaves I've seen have the ceramic plate on the side where the magnetron is so there's no space for a stirrer.
This rarely seemes to be an issue with other foreign made products like Microsoft, Apple, Amazon etc. I would've thought that one would want all critical infrastructure to be made in country.