GrannyGrunter
Well, I think it is just laziness. I am a very fast typist, I was a shorthand typist in the 60's and I can type Dear Husband faster than pressing the Caps lock on the keyboard and typing DH.
How lucky you are to be able to type fast. I use two fingers and have to look at what I am typing, and if I am typing a long post I find that by the time I post it the discussion has moved on and nobody cares. I didn't have to type in my working years, so I didn't develop that skill.
There must be many of us who take longer to type "Dear Husband" than they do to press the shift key while typing "DH" If it is a long and involved account of interactions between family members, shortening their names does speed up getting it written, and makes it shorter for the readers too. Incidentally, "DH" also covers "Dratted Husband" which is sometimes the point of the post.
Thre is no law that says that EVERYONE must use acronyms, just as there is no law that in everyday conversation everyone HAS to refer to their spouse as "Hubby" or "The Old Man". When someone does so, the hearer may wince but doesn't usually complain to the speaker.
I do a mixture - typed in full when I have plenty of time or I am writing something I want to be very clear, acronyms when my fingers are starting to ache. If you want to type everything out in full, then do so, your choice. As you get more familiar with the common aronyms, you will find that you understand them at once. Don't worry, in twelve years they haven't led to an outbrak of text-speak on Gransnet, so I think we are safe.