University rankings are not good shortcuts to finding the right schools to apply to. They typically rank entire universities and when the institution is not large enough, is teaching oriented instead of research oriented, or doesn’t qualify for some other reason, they are not included in a ranking comparison set. That is not the same thing has being a poor school or ranking low, it simply means they are not the kind of institution that the ranking publisher is reviewing.
The worst thing about this is that students may be influenced by rankings and apply to schools that they have no chance of getting into, and miss out on being part of a school that would otherwise be a great fit and is simply not the kind of school that ranking agencies are considering. Another negative outcome is that international students applying for funding from their home governments are frequently limited to only schools that show up in a ranking. These are only some of the unintended consequences of ranking universities and it is unfortunate that students suffer because of it.