One of the things I never understood about the hype around these Clojure GPU libraries is that there is a lot of marketing jumbo about how high-level it all is. Even the book for these libraries has the words "no C++!" half a dozen times on its ordering page [0].
However, these are just high-level libraries and you cannot write the GPU shaders in Clojure. You still must use C or C++ for that (depending on if you are going the CL or Cuda route), and your C/C++ code is embedded or called from the Clojure side. This is no different than using another high-level language like Python -- I mean it's focusing on a rather misleading and irrelevant detail. You can use Clojure or Python (or many other languages) to call OpenCL or Cuda shaders, or you can just use the libraries that call them for you. Clojure is not special in this regard.