To me this sounds pedantic, a good argument for a discretionary recruiting process and a good indicator of a bad interview/work experience. Why don't they instead try to define what superficial means? What do they expect from candidates in a way that can be measured? How many years of professional/research experience?

I'd guess that in the past, they've had far too many "candidates" who weren't candidates.

Nobody who meets that definition of "superficial" will self-select out of the process after reading that. Good candidates may, however.

right. for high performing competent people who don't need to work, the top reason they'd bounce is if you come across like a bunch of jerks.