Context of the news is very important. I'm certain that the couple who got legally married for legal reasons delivered the news in a different way to their friends than a couple who had intended to go through the ceremony and legalities from the beginning.

There's also a good deal of stimulus-response combined with social training via media and previous experience. Most Americans aren't socially equipped to offer the proper response to a marriage that has all the meaning of putting each on the other's auto insurance approved drivers, or the death of a relative that is a release from pain rather than an unexpected thing.