I like the company I work for, I really do.  
For specific reasons I am not willing to write here, though, I might have to go to work for another company. Provided that I work in an environment, where some data protection policies are enforced, I might have to leave the place the day I submit my resignations.

I would like HR to hear my voice though, and really understand what the strenghts and weaknesses of this company are. It is dumb / not beneficial / possible at all to ask for an exit interview, if I am not invited to have one?

I don't want to waste HR's time and I don't want to sound like the traitor trying to teach a lesson.