I’m not up to speed on the ESPN case. But note that the Supreme Court clarified in United States v. Cruikshank that only the federal government, and now the state governments though the 14th Amendment, are obligated to respect constitutionally enumerated rights. Ordinary citizens and employers do not have to respect constitutionally enumerated rights like the feds and state governments do imo.
Corrections, insights welcome.
It has always been the case that only Government can violate your constitutional rights.
"We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.--That to secure these rights, Governments are instituted among Men..."
Arguably, the "right to free expression" is included in the "among" above and is to be secured by government, all else being equal. "All else being equal" would take into account any restriction agreed to in a contractual arrangement and any restriction necessitated by a conflict with other rights.