Is crying in public immoral? No.
Is it always appropriate? No.
Is it always innappropriate? No.
Someone who cries in public to manipulate others is just being rude.
I also think that sometimes it's okay to cry once in a while about the so-called little things. If someone has had a horrible week, everything went wrong, it's Friday afternoon and they're trying to photocopy one last report and the machine eats it, well, I could understand if they needed to cry. However, I hope they would either start laughing at crying such a thing, or go to the washroom and calm down a bit. So often crying over a "little thing" is really crying over a series of nasty things. I don't see it as a failing or a character flaw... it just happens sometimes.
I think crying at a theatre is just like laughing at a theatre: it's cathartic.
And if something larger has happened, then really, people are going to cry in public. If they find out there's been a big event in their lives, their loved one's lives, something that happened around them, or something of great significance to the world, I can sympathise with crying in public.
Bombila said:
Crying (releasing tears) has known physiological benefits. Most of us could likely stand to do a bit more weeping, health-wise.
Losing control in public, or at work, however, can be problematical because of the effect on others. A person's basic urge is usually to comfort the weeper, or leave them to it, but if one is not intimately familiar with the person weeping, it's almost impossible to perceive which approach is appropriate, hence the feeling uncomfortable.
I guess from that all you can say is that the discomfort it may cause onlookers is of less importance, usually, than the need for the weeper to weep.
However, I know that there are occasions when a person will burst into tears at a moment where crying can only be seen as manipulative. A person who cries at a meeting, for example, out of frustration that things are not going their way, derails the concentration and thought processes of others at the meeting.
Sometimes crying at meetings has a reason, though. If someone is being used a scapegoat, or something is really going wrong for them, it is understandable that they may get frustrated and even drop a few tears.
However, I agree crying just to get one's way in a meeting is, well, kind of silly.