Not sure what hot weather has to do with working in a car factory, but it isn't "muh big business against the working and middle class". The working and middle class are ones who get buttfucked when they just hike the cost of the cars to cover the added expense. Do you think car companies just decide "oh man, sucks for us", or do they increase the prices and just open the next plant somewhere else? Millionaires and billionaires don't drive Volkswagons, so this money comes from the people who do. Yeah, no shit the governor thinks it's a bad decision when the main attraction of opening an auto factory in his state is gone.
The UAW IS big business, and they don't even make anything. They have a billion dollars in assets and Shawn Fain is rich entirely from skimming off people's paychecks. He isn't negotiating for other people to help them out, he's doing it to get rich himself.