That is a matter of subjectivity, and is not so easily proven in court. Speaking out against higher-ranking officers or the CiC can get him tossed out rather easily. It happened to the guy who called Obama a monkey, and said he hated him, and would never obey any orders from him.
Simply being a communist isn't enough.
Really? Feel free to cite the Uniform Code that's relevant.
Note that passages about partisan political action and such refer to campaigning or working with the party directly, not just holding certain political views. He might've breached the latter on conduct principles alone, but "being a communist" isn't a breach itself. Even if he's open and public about it.
Right. To be clear, I'm not saying this guy's actions are totally okay. I'm saying "being a communist" isn't objectionable or prosecutable. This guy should be in exactly the same trouble that he'd be in if his hat had read "Republicans will win" and he was a part of a Republican advocacy group.
Yeah, see the above response to Nasuuna. This is an issue of political conduct/advocacy, rather than an issue based on the ideals behind his views, which he's free to hold.
That's why I opened this by asking why the topic was about him being "pro-Communist", when the issue is his advocacy for any partisan political outlook while serving.
I don't think it matters if the person is doing a mundane routine job.
If someone is in a position involving classified information, by definition they have to sign away some of their freedoms that they would otherwise have in the public arena. If you want all your rights at all times, don't sign them away.