Is there any indication that hadn't happened here? Is Snap really that stupid? Did they not test this at all? If so, that's the big story.

Unspecified numbers of users complaining isn't a terribly sufficient story. I recall lots of facebook "boycotts" over the years ago over various UI changes, totally forgotten after a day or two. I suspect they actually a/b tested each change in small markets or test audiences and found usage increased after people got used to it. If Snap isn't doing that then that should be big news.