Earlier quoted context omitted.
So you can say whatever you want at your job without any repercussion from your employer? Yikes.
If you’re being sincere that’s a false characterization of the freedom of speech. It is not the ability to say whatever you want but it is the ability to share legitimate information or dissenting opinions, the former being the topic of OP. Employers should not be able to deny people their rights.
Freedom of speech means the government will not target you for expressing your opinion. It does not mean that your employer has to tolerate it. If I write an op-ed about how my employer makes a shoddy product, they are well within their legal rights to conduct their business how they see fit and terminate their business relationship with me. You seem to confuse freedom of speech with freedom from consequence of speech.