Although I wasn't involved in this "convert to comment" incident, I do it pretty regularly, as I am sure so does Steve. The system in fact flags and queues candidate posts for us every N hours. Usually these are things left by brand new users who don't have the rep to comment, so there's nothing contentious.
I don't know exactly how the system algorithm works (it seems to do with length, punctuation, and probably rep) or that this is how this started (not that that makes any difference). I just want to paint in the background a bit to help you see where we are coming from -- this is a judgement call we have to make everyday.
We also have the opportunity to follow up on and observe the results of the things we do every day, and over time form opinions about what works and what doesn't. Those opinions of course help make subsequent judgement calls. I am sure the workings of this not-so-invisible hand may often appear inconsistent because what's clear to us may not be so clear to others. And to be honest, I admit I am inconsistent, largely because I am often of two minds about some particular distinction and will try one approach, then another, but still not really settle for myself what the generic case is.
Looking at the answer you're referring to (which was converted verbatim to the first comment on the question), I would have to agree with Steve because it seems mostly like a lead up to this question:
Are you able to establish the connection with PuTTY?
That's not an answer. If you'd left that off, I'd probably consider it an excessively abbreviated answer, but still an answer if that's what you want to call it. I'm not saying ending that in a question was wrong, I think you were legitimately being helpful and this was a request for clarification.1
Here's the thing: Although I am constantly telling people this isn't a discussion forum, the amount of discussion I end up engaging in comments is certainly enough to brand me a hypocrite. Sort of. Discussion in comments is obviously necessary to some extent, the idea is to try and minimize it and not treat it as an opportunity to chat. We do have a (much neglected) chat room and in fact you have enough rep (>= 100) to create rooms as well. Pretty much everyone can access them (>= 20, meaning it takes two upvotes on a new user).
However, taking everything immediately to chat isn't necessary. A quick request for clarification in a comment on the question is great if it elicits a response because the information is then right there for everyone else to see (even better if it then gets edited into the question by you, or the OP, or someone). It seems to me that's exactly what this one is, and it is a shame the OP did not follow up because if you look at the accepted answer, ifermon had to refer to two different scenarios which an answer to your question could have resolved. That's inconsiderate of the OP, although I think many people who only ever ask questions do not realize this.
Part of the role of moderator is to be a little bit mean to people in certain situations, such as when a questioner does not bother to reply to comments, leading other people to more work than they should have had to do. The reason this is "a little bit mean" is because the OP likely just does not see the issue and will perceive me as trying to create a hassle, or acting power mad, or being dumb and annoying, etc.
Another example of having to seem mean would be this conversion-to-comment thing. By making that an answer, you were explicitly inviting the OP to reply in comments to a question. If you want to talk one-on-one, chat. If you want clarification on a question, ask in the comments. That's pretty clear cut.2 I can promise we could take this to Meta S.E. or poll all the world's moderators and the overwhelming majority are going to agree with Steve and I here. Not because they are moderators and we like to maintain a "blue wall", lol, but because I think the issue is very clear if you have enough experience trying to make things work better.
I think you are genuinely a helpful person, and there's nothing wrong with questioning our judgement, but have a little faith! Although I'm obviously biased, I really believe you are in good hands here moderation wise. Unfortunately, it is not always something I enjoy because of the perception issues, etc. I don't want to seem mean or annoying so please do everything right in the future. ;)
1. Something you can do that's fine is post an answer and ask a question (in comments on the question, not your answer), then use the information that comes out to refine your answer.
2. Part of the problem there that may not be obvious is you are then encouraging this very neophyte user to believe "answers" are individual discussion threads. Keep in mind people who want help may really, really want help (I'm sure we've all been there) and if you give them an easy way out of making an effort to do their homework and compose the question, plus the opportunity to hold hands, they'll take it. I didn't end up here because I don't like helping people or answering questions -- before S.E., I was one of those people with thousands of forum posts various places. A major reason S.E. has been a wild success (like, the major reason) is because people like me appreciate the structure. That's something I'm happy to stand up for, even if it does make me seem mean occasionally. I recognize the desire to jump in and start helping, but there are more and less efficient ways to do it, and it is a mistake to believe there is a limitless supply of help available and so using it efficiently doesn't matter.
