Crying can be a tremendously positive thing. It can offer a person the chance to acknowledge potentially painful feelings that could not be acknowledged in any other way. It also can provide an outlet for truely joyful feelings. In these settings, crying is a way of respecting one's feelings and giving them acknowledgement. This is a good thing.
It is my opinion that, if a person is in the setting of trying to teach someone else something or is trying to advocate a point, then they will naturally apologize for loosing their composure if they happen to cry because they recognize that crying tends to put pressure on their listeners. Crying in these settings communicates the message of "I feel so deeply and personally about this that it brings me to tears." Such a message can pressure people, whether intended or not, because it can create an obligation to "feel" the same way as the speaker or at least to raise their current level of feeling lest they risk feeling guilt. Because of this, a mature person tends to apologize for loosing their composure - not because they are apologizing for having deep feelings, but because they are apologizing for any pressure their audience may be feeling. This is considerate.
Another point to consider: crying is not always a stable indicator of feelings or convictions. People can cry for a number of different reasons - sometimes because of feelings completely independent of the subject they happen to be discussing. This can be confusing for an audience if a person has stepped forward to speak and they begin to cry while discussing something that really doesn't seem like a very emotional subject. An example of this is when I have observed people get up in religious settings in which they are attempting to share personal religious feelings. Sometimes people share very personal experiences and, naturally, tears well up in their eyes. However, there are others who get up to speak and, rather than sharing religious feelings, begin to speak about recent events that are quite ordinary and not religious in nature. They then begin to cry which presents a very odd scene because the tears don't line up with the content of what is being said. My personal understanding of such occurances is that these people are trying to share religious feelings but they are nervous and scared because of the audience they are facing. Thus, their fear is what is actually producing the tears in these instances. Their fear is also what is partially responsible for their retelling of recent ordinary events (sometimes called a "travel log") because they are scared and what has happened recently is the only thing that comes to their mind at that particular moment. Such a crying, travel log scenario is very different from when a person is sharing really meaningful experiences but sometimes people confuse the two as being equal or at least similar. I believe that these people who struggle really do want to share experiences of substance and the only thing that prevents them from doing so in an effective manner is a little bit of coaching and practice.
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