> The programmer in question, though, is not so hard: Send them an email to schedule the meeting with the hiring manager. That's not hard.

It is not trivial either. Neither side wants to show their full availability immediately and you eventually have to block multiple timeslots till a response comes in. On a call you can give out preferred times at first and if they aren't a match look for alternatives. And you can confirm on both calendars at once without blocking other slots as well. But yes, shouldn't be hard to manage ...