I'd say, generally, rankings are often fickle beasts, so don't put too much faith in any specific one you come across. Depending on the publisher, ordering rules, etc, you may get very different rankings for each school. To your specific question though, it's a fair bet to lump Masters programs in with their respective doctoral program, at least if you're looking for some prestige comparison.
That being said, particular Masters programs can be better than others in certain aspects (like affordability, access to research, focus on industry, etc) that may run counter to the institution's prestige ranking. For those things, it's best to research institutions within your specific field rather than look for some published blanket rankings anyway.
As to why there is no blanket Masters ranking, it is likely related to what I mentioned above: Masters programs are often geared toward students with specific goals in mind. Undergrad and doctoral programs are each generally focused on well-defined tasks, providing a foundation and establishing research competency, respectively, and thus perhaps easier (more valid) to compare. In obtaining Masters degrees, students' goals can run the gamut of possibilities. Some people are looking for career advancement (e.g. MBA, MEng, etc), others are looking to make a pivot in their field, and still others are looking for something else. It's tough to compare these programs because, with all the variables, you're really comparing apples and oranges.