Their interview process surely can handle "can this person code fizzbuzz", but it makes no sense to take time from one of your engineers to test this when it can be trivially handled by something like hackerrank.
I don't understand why people find this practice questionable, it saves time for both company and candidate.
But perhaps a different way of answering your question would be a more apt response?
Take this with a grain of salt, but in my experience of building organizations, it seems to me that in social systems, as opposed to engineering systems / code, the most powerful organizational forces are the second order and tertiary effects of the policies that are institutionally put in place. Not the first order effects.
The first order effect of using HR/LC easy questions might be that it weeds out people who really can't code in a language. And in that result, using HR and LC in your interview process, isn't a bad thing.
But the 2nd order effects of using HR/LC are often disastrous. Because once you start using HR/LC as your FizzBuzz question resource, you've made it easy for interviewers in your organization to start using HR/LC questions for more than just a FizzBuzz replacement. Maybe interviewers go to HR/LC for medium, hard questions. Maybe more?
HR/LC elevate what should be a small (though important!) part of the interview process, to one of the most important, hardest, and complex parts of the interview process. In most interviews I have witnessed in the last few years, this comes at the expense of other things that _should_ be more important parts of the interview process. And that's what is disasterous.
That's the issue with HackerRank and LeetCode. It is intentional from HR and LC's point of view. And is an unignorable, indeed one of the most important aspects of adopting a policy of using HR/LC in your organization.
I don't understand why people find this practice questionable, it saves time for both company and candidate.