That's certainly one way to look at it. Another way to look at it is that the above OP was just being thoughtful.

Recording and replaying opportunities to appear thoughtful, is not thoughtful.

It's merely artifice for the purpose of appearing thoughtful, which I find creepy.

But as I note in my initial comment: everyone is different.

Paper, and now computers, are one of the best ways we have learned to augment the human mind.

Is it creepy for someone to (with their brain alone) remember a personal detail like a birthday? If not, it shouldn't be creepy to remember it with an augmented brain.

There is a fuzziness here when your brain is augmented with information that you didn't have original access to, such as a shared calendar with birthdays on it, but I'm not sure how creepy using that information is - it almost certainly comes down to expectations of privacy with respect to that information.

As I attempted to express in my initial comment, I find it creepy when the details which are remembered exceed the level of expectation for the relationship between the people.

Remembering my birthday? Well, I know you wrote it down (or in OP case, it's in the HR file), but we have a relationship that is formalized around paperwork. So OK, whatevs.

Remembering my oldest child's birthday? There is no way in hell you remembered that organically. So I'm led to suspect that you made an active effort to log the detail for future use. And I have to envision you, listening to me casually discuss family ephemera, taking notes of items that might have some future value.

That's creepy, IMO. But I can accept that different people view it differently.

Nevertheless, if your goal is to create a connection between yourself and another person (as indicated in OP comment) -- you will not succeed if you fail to understand your audience. This is the idea I was attempting to express to OP.

The other person may choose to overlook your offensiveness, but they will not think more highly of you after the fact, than before. For certain definitions of "other person". Do with that what you will.

I take notes and for dates I think are important I put them in my calendar, but I also remember numbers easily so dates aren't a challenge for me. I have Aphantasia & Prosopagnosia so I don't waste a lot of brain space remembering what people look like :D (Or names for that matter, I'm terrible at names).

Seriously though, I would walk past that same co-worker in a shop out of context and not recognise them at all.

Context is always important, I don't just randomly trot out dates because I can. I've never once had a person react negatively to me doing this. Its not like I see you for the first time in a year at a BBQ and the first thing I do is look up in my CRM my notes from the last time we met. I'm not wearing Google Glasses to tell me your name, DOB and family details. I met a former colleague a few months ago randomly in the street, had a quick chat and went our separate ways. Ten minutes later I looked at my calendar and realised it was his birthday; I didn't run after him to wish him a happy birthday, but you can be sure next year I'll remember his birthday without my calendar because of that day.

I recognise some people might be offended, but my own experience and most of the literature I've read around establishing rapport, building emotional connections etc all point to people really liking it when you talk about them. So I will continue to use my method until evidence points me to someone else. I know I risk alienating people such as yourself but overall I feel I have better friendships and working relationships. I just hope if I make someone uncomfortable that they'll let me know, just as you did.

If I understand your argument, you think that:

(1) there is no way an acquaintance would remember your child's birthday organically,

(2) so if they do remember they have taken actions to remember,

(3) and the reason they took those actions was in order to give the appearance of caring about the relationship between you both.

(4) Furthermore, everybody on the receiving end of this interaction finds it distasteful or offensive, or at least will not think more highly of you because of it.

I think that (some of) these points may hold for some people, but don't hold in general.

1. For whatever reason, there are people who will remember things like this.

2. There are also people who may remember something like this in one situation, but not in general. For example, it just so happens that my wife's brother has the same birthday! We went out for his birthday last night, which prompts me to remember this detail about your child. So when I meet you soonafter, I ask "how did <eldest child> enjoy their birthday?"

3. The important part of this is the 'appearance of caring', I think. Is it weird for a presenter at a workshop to use memorisation techniques to remember the participants names? Is it weird to make flash cards about people you met from a networking event to memorise who they are and what they do? There is a really blurry line between the 'appearance of caring' and 'actually caring' and I'm not sure there is much of a meaningful distinction.

4. I'm part of a large family conversation online. Many of the posts are birthday wishes, often from people you might see once a year. The first post is often from one aunt in particular, who has obviously collated a list of the birthdays for the ~50 people in the chat. No-one thinks this is creepy, and everyone loves that she has gone to the extra effort to remember their birthdays. Posting birthday wishes to an old college acquaintance because facebook reminded you isn't creepy, but also isn't viewed as fondly becuase less effort is required. I think it's reasonable to imagine many people would be flattered that someone went to the trouble to remember personal details.

I hear your point though, and agree that it could be creepy - it really is about understanding your audience, as you say, however I think it is more likely to be appreciated than not.