I am the one who left the comment you quoted, so I'll provide some advice from that point of view.
If you open with "Where have you been?" or something similar, or ask it very early on, then cautious people very well could be unnerved. Even if I was not afraid of you, asking where I have been or am going is not necessarily rude, per se, but it seems odd out of context. Asked merely out of the blue, I would assume that the other person is either comparing their trip to mine and might even try to 1-up me with something like "Ow wow, that's neat. I've come twice that far." or the like, or that they are a bit stalker-ish. I will not assume that you definitely are a stalker, but I will be wary that you could be.
If, on the other hand, I stopped and talked to you for longer than a passing nicety, then there could be situations in which you could ask about my travels. After talking about the weather, or about the trail conditions, or about your dogs, or something else, if you said "I still have a long walk ahead of me too. 15 more miles just for today. What about you? Where are you headed?" That would sound a whole lot better. And maybe that was even what you had in mind in your original answer that I commented on. In this situation, I might even tell you all about my trip and have a great conversation with you about it.
It could also work, even up front, if it was in the context of some reason why that information was useful to you. "Hey, I am looking for a river that is supposed to be up ahead and was wondering if you came from that way?" or "Hello. I just ran into [insert appropriate obstacle] in the path a couple miles back beyond the fork. Which way are you going?" Then obviously that is also fine.
But just by itself, with no conversational context, I'm likely to raise an eyebrow and respond with "I have at least a few miles to go. I'll find out when I get there." and try to end the conversation short. Some people are that abrupt and are just being friendly, but generally that is an odd context-less question. And I don't want to take the risk that you might be up to no good (no good doesn't even need to be evil; I have heard of people playing pranks on others, something I would still want to avoid).
Another good point inspired by the answer by @henning, adding my comment there to my answer:
One of the biggest worries is that you would follow me. However, the following does not even need to be through any malice. I would worry that it was, but it is still awkward to be followed when nothing bad is afoot.
I have actually had socially odd people follow me before and continue trying to be friendly to me. This is rare, but it has happened to me more than once. Sometimes I have even tried to get them to stop following me but they don't seem to get that what they are doing is not socially acceptable.
In fact, after trying to be extra nice to this one guy one time for as long as I could bear, I outright told him that I did not want him to keep following me and trying to talk to me; he acted like I was the one in the wrong, and he actually asked me if I needed a hug... yes, that's right, I was creeped out by him, and he asked me if I needed a hug. And I truly believe that he was not out to steal from me nor to hurt me, that he was just a socially odd person. I get socially odd - I'm somewhat socially odd, but there is weird and then there is "I hope I am never in that situation again" level of awkward.
Perhaps my experiences are part of what makes this difference between you and I.
So being leery of you does not necessarily mean I think you are going to attack my camp at night. If you're creepy enough, sure, maybe that could be a concern too. But I do not want the potential for any problems, whether they be fear of burglary, or even if they are just you thinking I need a hug.