The problem there is that natural language processing is a highly specialized field, not something one can expect a generic SRE to know unless it's explicitly mentioned in the posting. I'm willing to bet the posting said nothing about NLP.

I could ask a detailed question on cryptography, robotics or reverse-engineering, and it would be just as (ir)relevant to the SRE. Computer science is a much broader field than your niche area. Arbitrary goal-posts are arbitrary.