The stereotypical false positive is a competition programmer who aces whiteboard puzzles and leetcode type problems but isn't actually a good software engineer. They fall down at all the other parts that aren't clever programming.

Thankfully those are usually junior hires and can often be mentored into a good or excellent engineer.

There are also lots of people who are just bad engineers but memorize Leetcode problems. Most of Leetcode is memorization, and most of the people I see get hired at Leetcode establishments aren’t good engineers.

It’s just a bad test, why are people so hung up in it? Cause Google does it?

People are hung up on it because it's the gate to making ridiculous amounts of money doing what we all enjoy.

Also, because there isn't really a "good" option for interviewing (especially at scale), the door is always left open for endless circular debates on the topic.

False positives surely exist, but in my experience the challenges are rigorous enough and preparation requires enough patience, that there's a certain competency floor here that makes this less of a problem for the company. Every single engineer I met there ranged from competent to "10x", contrary to a neighboring comment.

I do think there's something of an obsession to minimise false positives at the expense of false negatives. The companies are succeeding at this, which I find foolhardy as they lose the opportunity to hire even more of the high performers who can't or won't jump through the hoops.

To be fair FAANG are probably large enough now that they can get by with a mix of average engineers at this point as well. They really don't need the best of the best. It's all at scale now and there isn't time for individual attention.