I do not have Moon in Capricorn, but know of several people who do. I have a... "distaste" for their apparently emotionless selves. They may have achieved much in life, sure, but I really dislike their cold, emotionless nature. It's being near a cold stone. Perhaps achievement is the thing that satisfies their moon Granted, there could very well be other factors contributing to the feeling, but I've noticed a pattern that rubs me the wrong way. Not sure if others sense anything similar.
Perhaps it has more to do with the types of people you attract? Or, those particular people for some reason, show that side of themselves more when they are around you? It's definitely true that people act differently around different people and that sometimes a person brings out their worst traits. Some people clash and some people click. Or, rather, sometimes a particular trait stands out too much to someone because it grates on their nerves.
I know I've experienced that last one before. It usually grates on me because its a trait that is completely different from my own tendencies. Sometimes I perceive this is because I secretly want to be more like that and am resentful or I just think its foolish/annoying and too self-conscious.
I think most of the traits you describe are too stereotypical of the sign to be accurate for most people and might have more to do with aspects and other signs than solely being the fault of the moon in capriccorn.
The whole chart should be looked at rather than singling out one planet.
A person with their sun in pisces with moon in capricorn will be VERY different, usually at least, than a sun in virgo with that placement. Or, a moon conjunct saturn in capricorn will be highly different than moon in capricorn trine venus.
Certain aspects can soften the moon in capricorn placement, and others can exacerbate their weaknesses.
I have two examples of people with moon in capricorn.
I have a friend who has a capricorn moon, but she also has sun/merc/venus/saturn and uranus in sag!
In general, she is excitable (which makes her fun) and she has no trouble expressing her opinion or her feelings. She is warm and social, though not overly so. She has many friends and is very active. She is very open and shares easily, even things that make her look bad or silly or insecure. Family is extremely important to her. She is not overly ambitious. I would say a good healthy amount without it being obvious. She is competitive but not annoyingly so. She is far from selfish. In her case, I think all her sagittarius influences outweigh her capricorn moon. She also has sun and venus in conjuntion to uranus. I would say one fault of hers is a tendency to nag her husband (haven't noticed her doing it with others) and her tendency to complain/whine. Overall,she is upbeat, but I notice sometimes she gets in moods where she complains a lot. Considering sag, I would say its more of a capricorn trait.
I was shocked when I looked up her birthchart. I never would have suspected moon in capricorn!
Now, the second example:
I am a scorpio with moon in capricorn. Yes, I am reserved (very) and I do not express my emotions/feelings very well. However, I am far from cold. Most people would describe me as very affectionate, caring and generous. If they thought about it, they would probably realise that I don't talk about myself or my feelings or fears very often, if at all, and while I can appear aloof and distant at first meeting, once I warm up I let my guard down enough to be moderately chatty and friendly. In general, I am a very friendly amiable person. With friends I can be quite talkative and it is with them that I show my sagittarian traits.
With family, I am very caring and generous. I am very dependable. It is important for me to be there for them and help whenever I can. I am always the mediator and the comforter. I am also the person who gives sound advice and am usually the one to dissuade others from doing something I deem risky or foolish.
With strangers, especially in a group setting, I appear to have an icy reserve-sometimes more of a melancholic distance really--and I can be somewhat curt (not in a rude way, just brief and to the point in speech). In my case I do this due to extreme shyness. I try to talk as little as possible. I am not like this at all with friends or people I feel comfortable with.
I have most of the negative traits of capricorn in terms of emotional hangups, but I don't have a lot of the typical traits. I am not concerned with status or achievement (would probably be better if I was). I am not ambitious or concerned about status quo and am not a traditional minded person. I try really hard not to offend/disappoint or hurt anyones feelings.
In my case I think I lack some of the typical capricorn traits due to my venus in sag and aspects to uranus. Sun/merc and venus conjunct uranus. My ascendant in leo and loads of planets in house 5. I have a few sextiles to my moon which helps immensely I think.
But I also have moon square saturn and pluto which makes it all a lot worse! That is really where the reserve, the depressive tendency and need to feel in control of my emotions comes into play. Saturn is very restrictive. Self contained is a good word for it. I am also overly cautious with certain things (esp with money!)
In my friends case, her strong sagittarian influence greatly outweighs most of the negative capricorn traits. It definitely softens the reserve of the placement and most definitely adds more zest/spontaneity and action to capricorn which can be a bit dour and routine.
In my case, it is also the sagittarius (I have sun and mercury in conjunction to jupiter as well). But it is also my leo rising adding warmth and affection and PLAYFULNESS. I think both sag and leo also give a person a more youthful approach to life that capricorn definitely lacks.
In short (not!), its really hard to generalize any sign placement, as there is so much going on in a chart. While there ARE people out there who are cold and overly concerned with achievement and status and status quo, you will find just as many with other moon placements as ones with capricorn moon. Maybe some of them have moon square saturn with their moon in a different placement. Or some other planetary combination that makes a similar impression to capricorn.