I'm with what you're saying, but what I find frustrating is that it seems then fair to say that the recruiter has a professional responsibility to their clients

I'm with what you're saying, but what I find frustrating is that it seems then fair to say that the recruiter has a professional responsibility to their clients to know something about software in order to effectively screen candidates. But 99% of recruiters I've ever dealt with don't even pretend to make an effort. Interestingly, most IT managers hate recruiters as much or more than I do, but - like me - they're at the mercy of their corporations' "preferred vendor lists".