Maybe the CEO got a not so gentle nudge from the investors to hurry up and hire somebody and you were the one they were interviewing next. Stuff like that happens a lot. The process is more about outside factors than the actual interviewing process itself.
But when these conversations turn into arguments it all comes down to some applicants being more "qualified."
There are lots of reasons people get hired to do jobs they've never done before and lot of those reasons are subjective.