The "cram" part of "cram schools" isn't about the facilities. It's about cramming as much info into the student in the shortest amount of time.
There's a wikipedia article about cram schools:
https://en.wikipedia.org/wiki/Cram_school
From the article:
A cram school, informally called crammer and colloquially also referred to as test-prep or exam factory, is a specialized school that trains its students to achieve particular goals, most commonly to pass the entrance examinations of high schools, or universities. The English name is derived from the slang term "cramming", meaning to study hard or to study a large amount of material in a short period of time.
Cram schools may specialize in a particular subject or subjects, or may be aligned with particular schools. Special cram schools that prepare students to re-take failed entrance examinations are also common. As the name suggests, the aim of a cram school is generally to impart as much information to its students as possible in the shortest period of time. The goal is to enable the students to obtain a required grade in particular examinations, or to satisfy other entrance requirements such as language skill (e.g.: IELTS). Cram schools are sometimes criticized, along with the countries in which they are prevalent, for a focus on rote learning and a lack of training in critical thinking and analysis.