Well it's lose lose for applicants then. We get shuffled aside by non-technical HR reps and automated processes for lacking specific keywords that often aren't even relevant, and then we also get rejected for playing the game. I would have continued the interview.
I can understand why you’d reject someone for that, but I have to wonder: would you have seen the resume at all without the keyword stuffing, and had you seen it, sans said keywords, would you have interviewed them anyway?