IMO, you'e taking her comment "it's about infringement" a little too literally.  Yes, our team sued the defendants for infringement, so ultimately, that's what it's all about.

Now, how does one defend against such an allegation?  Proving invalidity of the patents is one avenue.  Proving that you don't infringe in any of your products is another.  And yes, the court (and jury) can hear arguments involving validity of the patents I believe.  I don't think it's solely a USPTO "call". 

And I would think that, when the day is done, if there were a conflict in the findings of the court versus the USPTO, the matter would be resolved at a higher court; if not as part of the standard procedure, then as prompted by whichever party lost the court case due to this issue via appeal.

Open to corrections.....

'Cuz I KNOW nuttin'!

SGE