E.g., even now I have next to no knowledge of Python because I've never used it in detail. Nor do I claim to have done on my CV. An interview where I get asked "Lots of Python" questions (see the second round section on OP) isn't going to go well, and even as a veteran engineer with a fairly thick skin I'm not going to be terribly happy about enduring it.
This kind of problem is exacerbated if your interviewers haven't done sufficient prep so, instead of realising that you don't know anything about a particular technology, they take your poor performance in that area as an indication that you overall suck.
I understand why companies ask these standardised batches of questions: we all know that IT is full of jokers who claim proficiency in technologies where in reality they have very limited exposure and skill. But if somebody's actually told you they don't know something then you're simply wasting your time and theirs, and creating an unnecessarily negative experience, by going through the motions.
The thing with Google is that, because so many people want to work there, there will likely be somebody in that mass of candidates that has reasonable knowledge in all those areas, and they can afford to be that picky. Most companies can't which, overall, I think is a good thing.