Was he being forced or compelled to offload his thinking to a machine?
I probably don’t share his sentiments, but that’s no different from being compelled to think in certain mandated ways (offloading being just a particular case of it), which is certainly a bad idea. If that was the case, I find it weird that he used a religious exemption mechanism, but glad he can act and think freely, the way he desires.
However, he may not have a choice of tool use or peers, and be compelled to send work to, or process results done by a non-human system, if that’s a part of his organization system (external to him with regards to duties and responsibilities). To grant him an exemption would be to discriminate upon others, no different how he can’t refuse to work with, say, a Satanist. Or a cyborg transhumanist. If that’s the case and he just refuses to feed his thinking (his part of the job) to an AI (not his part of the job), then that’s him being a zealot pushing his religious views on others. In such a case, I can quite clearly see why he went for a religious exemption, huh.
His own part of the job, his responsibilities - yes, of course he can’t be compelled on how he does it. Anything outside of that - nope, his religious beliefs end there, not his thinking - not for him to say how to do it, or refuse to interact.