Speaking as someone who reads around N2 level but can barely ask for directions, this is on the mark. I self-study and have few means or reasons to practice speaking, so it's never been a priority for me.

But I think this arrangement is actually quite...realistic? Charitable? It's very hard to become conversationally fluent in a language - especially one as foreign for most learners as Japanese is - without the kind of serious immersion you can most easily get just by living in the country (though maybe I'm just making excuses for myself). Asking learners to do the groundwork and get the foundations at home before getting hit with that immersion is going to set them up for success, facilitate their smooth integration, and demonstrates a candidate's seriousness. My impression is that in such a situation most learners will improve their speaking skills quickly, but there's no getting around months and years of drilling kanji.