A corporation benefits all of its owners (and hopefully its employees too, though that's not a given, sadly). In the case of Apple or Dow or Boeing, that's millions of people.
Ordinary people are free to combine their voice via unions or their own lobbyists.
Communicating with your representatives is protected speech. The problem is campaign finance.
Unfortunately, millions of people is still less than 4% of the US population generously.
Employees are a cost center. The idea is to get as much as possible for as low a cost as possible. That's business and why employees can only win if they band together because they'd like to get as much as possible for as little work as possible. Those are diametrically opposed interests. You can change that equation a lot if the employees are the owners.
Ordinary people are free to combine their voice via unions or their own lobbyists.
Communicating with your representatives is protected speech. The problem is campaign finance.