That concept became controversial 57 years ago with the passage of the Civil Rights Act in 1964 and the controversial nature of it has been strengthened over the decades since through a multitude of hostile workplace laws building on the CRA.
What those laws mean is hiring an employee, doubly so for a manager like the man in question, who has published a high profile book disparaging a protected class of people opens up the company itself to lawsuits on the basis of discrimination relating to a hostile workplace if a single member of that protected class is (or even feels) mistreated in some way because it’s evidence the company should’ve known about the potential hostile environment and did nothing to prevent it.
And so it’s clear, no this is not the same thing as cancel culture based on a tweet or forum post or even on the scale of Amazon banning Parler. It’s not the same as James Damore and Google. Those all do not necessarily meet the standard of public speech while this guy went and published a book which very clearly does. This is a half a century plus of laws and cases establishing precedent and companies acting in a way to prevent costly lawsuits.
No well run company would open themselves up to the legal risk involved in hiring or keeping on someone like this for a management role, especially after it was clearly brought to light in this manner. Apple’s HR department is almost definitely currently trying to figure out what mistake resulted in him not getting filtered out earlier in the process so they can prevent this from happening again.
"Can he do the job?" has not been the only thing that matters, and in fact the situation described in this instance has mattered, for over a half century, I’m guessing longer than you’ve been alive. Not because of woke mobs or free speech or any other recent political talking points or even really about Apple caring about sexism. It’s about avoiding clear cut legal and financial risk period.