Actually, I think informed people understand that polygraphy is indeed a ruse, to the extent that it necessarily involves the polygraph operator lying to and otherwise deceiving the person being "tested." The late Dr. Drew Richardson enumerated some of the examiner deceptions inherent in polygraphy here:

https://antipolygraph.org/cgi-bin/forums/YaBB.pl?num=999288767/28#28

I can see how you might consider polygraphy not to be a ruse, to the extent that outcomes depend on how the polygraph charts are scored, but in broad terms, polygraph "testing" is an interrogation masquerading as a test.

I agree with you that not everyone gets accused of hiding something. And you're right that those who pass don't (usually) get interrogated. And yet interrogation is a key component of polygraphy, and it is heavily emphasized in polygraph examiner training.

I think Poly Exposer, while engaging in some hyperbole, makes an overall valid point.