That's a non-credible excuse. If it's really about how you deal with adversarial situations, there's no reason for coding to be involved at all. There are plenty of other scenarios you could role-play that are more realistic and/or more informative wrt what software engineers actually do. Why don't people do those things instead? Generally, because it was never really about communication skills or reactions to stressful/adversarial situations. That's just the rationalization that people who actually did intend to measure coding skill come up with when they're forced to admit that the tool they've chosen is spectacularly ill suited to that purpose. Nobody wants to admit they've wasted so much of their own and others' time.
...and the rest of us are supposed to read his mind? Since we're talking about communication skills here, I submit that good communication skills might include stating one's meaning more clearly.
Being a good developer requires the ability to write logical, maintainable code of course, but equally it also requires having the ability to talk to other developers, to work with a team, and to explain technical problems to non-technical people. Those are soft skills.