Oooh, what's my prize?

Yup, I pretty much agree with your assessment. It was quite the interesting rabbit hole to go down. But at least for me, it became anti-productive and unhealthy. I found much better uses of my time.

buybuydandavis may not want his username Google'ably related to someone running an organization he considers phygish. Especially if it is a phyg, in which case there's a non-negligible probability of personal risk by openly using the name. If that's the case, then it makes sense that he didn't use the anarchist's name in his post while he was fine with using Rand's. Rot13 helps reduce the chance of risk to (what I see as) negligible levels. If this is the case, then I see the use of rot13 as appropriate.

Admittedly, he could have has a slew of other reasons for not using the name. He could just not want to give the guy the traffic. Or maybe he's not as well known as Rand, and using the name wouldn't be edifying to most readers. Or maybe it wasn't a conscious decision at all. If any of these kind of reasons are the case, then the rot13 was unnecessary.

So I had to make a quick judgment under uncertainty, so I decided to use rot13 because and err on the side of caution. If I was going to make a mistake, I wanted to ensure I'd make the least costly mistake. From my perspective, the extra few seconds per person reading the comment is worth that assurance.

If there's a better standard/heuristic by which to use rot13, or if I have broken any of LW's rules by using it the way I did, please let me know. I'd be happy to correct my behavior. Otherwise, I've explained my reasoning and will politely tap out of the conversation. Other commenters can feel free to up/down vote as they feel appropriate.

Edit: Regarding this, buybuydandavis later commented that

I thought the use [of rot13] was appropriate in response to my deliberately leaving his name out of it; I found it both perceptive and courteous.