Duolingo never even claimed they teach up to fluency. How much they promiss depends on language, but most developed one ends with B1. The fluency complaint is

Duolingo never even claimed they teach up to fluency. How much they promiss depends on language, but most developed one ends with B1. The fluency complaint is completely nonsensical. There is no in person class that would make you fluent, there is no textbook that would make you fluent. It is possible to criticize Duolingo, but the fluency claim kind of show you don't know what you talk about.