Thanks for your input. I've tried both. As I said, the observation was based on "personal experience". I ended up liking the 80 mm stem.
In fact, I did ~ 20 mi flat on the day I made the changes. The next day I did my weekly South Cal. Palos Verdes ride, with a descent on switchbacks. Luckily by the time I already knew the old bike handled quite differently. I had previously done the same ride tens of times. It took me a couple of times to get used to it on the drop with the new stem.

If it's a new bike or new route, everybody would slow down descending a switchback. Old bike, same old switchback descent of a weekly route, but with a new shorter stem, be careful. FYI, the segment I was talking about
https://www.strava.com/segments/6537930

It's YOUR bike, and YOUR back. If that is what you want, then try it. If you like it that way, keep it that way. If not, go longer, or shorter, and back to the same. If somebody doesn't like it, well isn't that just too bad. Bless their heart!

I have a 54cm bike with a 120mm stem, a 56 with a 100 and three 57's with 90mm stems. I'll take the 57's with a short stem any day of the week. I like quick handling but I've never had trouble controlling a so-called "twitchy" bike.

After tweaking my fit a month or 2 ago, I went down to a 90mm from a 100mm stem on my LG 55 ST/57 TT size bike. Works for me.

Yeap. They are probably popular among those many who don't know that race configuration can really hurt. Such configuration can be found without the need to radically cut the stem, but most of us don't know how to search for them when they buy. Like me.

That short and shallow handlebar came with the bike. I don't particularly like it, but I've got used with it. I noticed they are very much used - might be due savings in weight and cost...