Let me get this right: private companies/citizens can drop business from anybody with zero notice and any amount of harm because "they're private", but private

Let me get this right: private companies/citizens can drop business from anybody with zero notice and any amount of harm because "they're private", but private companies/citizens can't express criticism because harm? Do I get that right, is that your reasoning? Private entities you like can do anything and private entities you don't like can't do anything to the ones you like, because?