You're being rather reductive. Just because someone is in a 'working class job' doest diminish their intellect. I've encountered many working class folks with a lot of knowledge in the fields they were in (electricians, plumbers, mechanics, etc).
Working class to me means Walmart, Mcdonalds, and Jack Generic Construction LLC.
Working class to most people just means that they do manual labor. They work outside and in factories building and moving physical things be it burgers or buildings or balloon animals. The key seems to be that they don't generally sit at a desk with a computer on it for 8hrs a day.