Clojure is also a hybrid. The other part is called Java or Javascript. This is claimed as an advantage, since there is already a lot of functionality in another language to be reused by a direct interface. Some stuff is simply deferred to the host language and since the other part is based on OOP, applications will then be a mix of more FP-oriented code calling OOP-oriented code.
This is an implementation detail, and doesn't affect the API presented to the user. For example, consider the clj-http library that's backed by the Apache http Java library internally https://github.com/dakrone/clj-http . As a user of clj-http, I don't know or care about the fact that it's a wrapper around OOP code.
Furthermore, if you wanted to, you could reimplement the internals in Clojure and the users of the library wouldn't be affected.
Being able to leverage existing mature libraries is a huge advantage, and the fact that they can be used via idiomatic functional APIs provides the best of both worlds experience.
