If 'free speech' protected people from getting fired you'd see retail workers cussing out rude customers without fear of losing their jobs. BTW, all states besides Montana are at-will employment states, although most states have exemptions for public sector, union and contract jobs and obvious stuff like someone getting fired just before they get their retirement, being fired because of your race, gender, etc. (protected class status), or someone being fired because they won't break the law. Still, some states, such as Alabama, have no exemptions on the books, although some instances are federally protected.