Treason is not protected by the First Amendment.
But you refuse to understand this because you have a political ax to grind.
You may find these remarks disloyal. I find them unadmirable, distasteful and warmongering, not to mention ill-advised. If they were treasonous, they would be prosecuted.
Treason is a crime. Political dissent is not. Political dissent sometimes takes harsh forms. That doesn't make it treason.
Now, if the writer were raising money to send to the insurgents, that would be different.
Fortunately for us all, the US does not prosecute people based on what you can only imagine.