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