I’m not sure that the general public have as much faith in the police as they once did, which might be adding to speculation and criticism.
The man who killed Libby Squires had been exposing himself to young women, in that area, for months (possibly even to Libby herself, but we will never know if that was the same man). He was also looking in windows. The reports weren’t followed up in a serious way and links between them weren’t made.
We also know about the history of the man who killed Sarah Everard.
So, the “what if?” element is frightening for women in the area.
There are parts of the story that don’t fit logically with falling in the river. The phone being on the floor is one of them.
Why bend down and place a phone on the floor when there is a bench so close? It seems more likely that the phone was dropped there. Why?
If she fell in, why wasn’t the dog muddy or wet or trying to get into the river?
If she is in the river, how do we know that someone didn’t push her in? The assumption that she fell means it wasn’t treated as a criminal investigation in the beginning, the public are allowed to wonder if that was a mistake and if more women are at risk because of it.
People are trying to fill in the blanks to make sense of it.