Giving each applicant a tailored test also opens yourself to allegations of discrimination.
As for leet code vs an actually relevant test - I think this is probably laziness on the interviewer's part. Coming up with a good test (and keeping it up to date) is hard, and leet code questions are "good enough" to filter out the people who don't know what they are doing. Remember, most companies are fine with a high false negative rate if it keeps false positives low.
Is discrimination even illegal? I thought unless it was a protected class, discrimination is ok. Unless you're giving all black people a shittier test or something I feel like it's a long and expensive road ahead of someone pursuing legal action, with probably not much to gain and no attorney particularly interested unless it is some class action against a big company.
> I thought unless it was a protected class, discrimination is ok.
That is also my understanding, but everyone except young white males are in a protected class. Granted, young white males are pretty common in tech, but you would still be wise to design your HR practices in such a way as to avoid lawsuits.
Agreed it would be wise to consider lawsuits when hiring. I do think though that's only one part of the equation. What you want to really optimize for is maximizing profit. Maximized profit may mean paying out lawsuits is cheaper than losing good candidates or implementing a poor or ineffective hiring process. There's also the risk of implementing a hiring process for which the expense of minimizing lawsuits is greater than the potential lawsuits themselves.
As for leet code vs an actually relevant test - I think this is probably laziness on the interviewer's part. Coming up with a good test (and keeping it up to date) is hard, and leet code questions are "good enough" to filter out the people who don't know what they are doing. Remember, most companies are fine with a high false negative rate if it keeps false positives low.