Your first interpretation wasn't the case in this specific ad, because the "minimum 5-10 year experience" was on the list of "essential experience and skills" and there was a separate list of "desirables".
Your second explanation just supports my original infuriation - just state the range that you're interested in, without calling it a minimum.
Actually, I got that job, I'm still working for the company, but to your last point, I have to say it's hilarious how bad our communications dept is at communicating to the rest of the company.
But - I wouldn't be surprised actually. What I am surprised with is what kind of applicants I get even with requirements like that (although more precise) in the job ad.