OpenCL/CUDA are GPGPU programming languages - that's something we're getting to soon :) We previously exposed OpenCL as an extension, but took it out because it's a nightmare to support. We're looking at it again at the moment - it's pretty challenging to write GPU code, so it's hard to see how much benefit developers will get from it until we can target nicely from KL. One for the longer term :)
The rationale for creating KL was that we had some specific goals, and we couldn't find an existing language that did everything we wanted - the requirement of being high-performance _and_ easy to use was critical. We also had security concerns (we started out as a browser plug-in), so it also had to be pointerless. Given that we have a fairly narrow scope (writing high-performance operator code), we decided the best path was a DSL. If we didn't have the security concern, we would have stuck with C++ - but that wouldn't have had the lower bar to entry that KL has.
My co-founder who wrote KL still thinks we were crazy to do it - 'the world does not need another language' :)
