Overfitting? Sure. But gaming the system? I disagree. Hell, I've heard of companies giving candidates the book to help them prepare for the interview. It's not ideal but this is what the system expects.
Can still hate them for playing the game, if that involves disdain for ethical principles one actually believes in
FAANG will usually send you a few slides on what algorithms and data structures to prepare.
I just started interviewing with FB and got prep slides, two courses on educative.io, a 27 page document on the origins and purpose of the role, two 45 minute intro calls, and two 45 minute prep calls so far, and a recommendation to study up on a bunch of problems on leetcode in addition. I don't know how the rest of FAANG compares but Facebook drops a mountain of prep material for candidates.