Why? Because it's a discussion about a change and these are some results.

Seems normal to talk about impact of decisions.

In this specific instance I was talking about my experience of unintentionally quitting my Twitter habit, so the comments where people describe how they also stopped using it are relevant. But I wouldn't be so quick to assume sour grapes, otherwise. It could be that these people found their experience of quitting Twitter to be pretty transformative and fulfilling and genuinely want to let others know about it.

I suppose they do it for themselves, a public statement that reinforces and legitimises their choice.

It doesn't contribute or take away anything from society.

It makes them happy and doesn't hurt anyone. Let people be :)

I did not say anywhere that I was happier, rather I was surprised that something I feverishly would check constantly multiple times a day could disappear and I wouldn't have any problem with it or urge to get it back. It's anecdotal but I've had friends who have also disconnected and realized that it doesn't seem to change anything, most of the information you consume is crap and forgotten.