I still have no idea what actual information this is supposed to convey. Or is it more of a "rah rah, evolution!" reaction thing?
You need something to compare it to; it's right in the article: "For comparison, humans and chimpanzees split somewhere between 5 and 7 million years ago"
So mice and rats diverged somewhere between 12 and 24 million years ago, while the range is 5 to 7M for humans and chimps. Humans and Chimps are very different and we'd certainly not try to treat chimpanzees as 'small humans' in a lab setting. Yet we tried to do so with mice, treating them as small rats.
Just a linear comparison would tell you that rats and mice have had 3 times as long to diverge as humans, making it a good chance that they're more different than humans and chimps are, even excluding that a generation of rats/mice can be measured in months when it's decades for humans and chimps.
As for the huge range - "He left the highway somewhere in Nebraska" is an overly broad area to search for an escaped felon, but if it's the best the investigators can come up with at the moment, it's the best they can come up with. 'Specification' is already a vague line, and without DNA to compare, or even enough intact skeletal remains, it can be tough.