Who considers Russian disinformation protected free speech?

Personally I don't. It's not speech from an American but rather a foreign country (or sometimes not even a human).

And it incites harm, which is one of the restrictions that can be placed on speech.

You support freedom of speech, but only for citizens of your country?

I support other countries establishing free speech laws. And in general the protection of non-US citizen speech within the US, especially foreign reporters.

But that doesn't have anything to do with constitutionally protecting 3rd party nations using platforms/speech for propaganda in our (or any other opposing) country.

Seems ridiculous on its face to try to confuse or equate the two and argue the point.

The US Constitution. Or better, the usual interpretation thereof.