There's a very sinister reason for this particular bit of gatekeeping: racism. To keep the profession racially pure (limited to whites and Indians of good caste), it's necessary to have an excuse to keep blacks and Latinos out of it, some of whom might actually be otherwise very well qualified to do the work. So we say they're just in it for the paycheck. Or in the case of a "coding boot camp," we say the applicant is way too interested in the hiring partners and not too interested in coding. The applicant does FizzBuzz well enough but too fast or too slow, either can be interpreted as meaning the applicant doesn't love coding and is therefore unsuitable.