The first amendment only applies to the government. The government cannot punish you for speech or expression, nor can compel speech or expression. There can be no penalties from the government.

It does not apply to your employer. Jimmy KImmel's employer is free to punish him for his speech and expression, and to compel his speech and expression, as they see fit. (within the confines of his contract, of course).

In order to get an FCC license, a station has to serve the publics interest. Those licenses are granted to the local affiliates. If the members of the public think the station isnt serving the public interest, they could lose their license. It was the local affiliates that complained to ABC about Kimmel.

Can the government not fire someone over their speech?