I don't think that's accurate. I don't think anyone believed that joining a company would -- for example -- mean that they were no longer allowed to make financial contributions, individually, to political campaigns.
Citizens United affirmed that it was ok for corporations to use corporate funds to make political speech via financial contributions. Not allowing that would not imply that people who work for a corporation have lost their individual first amendment rights.
Citizens United affirmed that it was ok for corporations to use corporate funds to make political speech via financial contributions. Not allowing that would not imply that people who work for a corporation have lost their individual first amendment rights.