There are people who love divorces, love interacting with them, and love watching people go through them. It’s a cottage market in gossip futures. Social media is designed around gossip futures by people with questionable character. So you answered your own question ;) more shit piled onto the heap!

Two possible reasons:

1. Attention.

2. You a have a public image that includes you being married and social media is one of the main channels over which you reach the people who know you. Now you get divorced and you do not want these people to have the false image of you being happily married and potentially even getting comments referencing your marriage anymore.

Desperate need for attention I'd imagine

Validation that her feelings/ her view is correct.

No one(*almost) is posting to reddits AITA(am I the asshole) expecting to hear that they are wrong.

This is also how echo chambers form.

Could be a lot easier to rip off the band-aid all at once rather than pen a hand written note to dozens or more mutuals with subtle hints of "please stop sending couples invitations to social events"

Why would you not talk about your divorce ? It's also a part of your life