They had an opportunity to evaluate your resume or CV before inviting you in for an interview. If it was a hard requirement for them, they shouldn't have invited you in for an interview. The only time you're really wasting is the time of the person who is screening resumes.
> Yes, this has happened to me. On the up side I now have a list of a few companies I know I won't work for unless I'm desperate.
I'm sorry that happened to you! What a terrible experience. It's definitely good to keep that list of places you know you should avoid.
"Did you work with <technology in requirements> at company Y?"
"No, I worked with <technologies listed on resume>"
"Then where did you work with <technology in requirements>?"
"I haven't"
Cue rant about wasting everybody's time...
The advice is still good; the requirements are really more of "strong desire" than actual requirements, and if you look at the typical requirements listing, its' unlikely that they will find enough people at the salary they offer to fit all of them anyways.