Yea, I used to get annoyed when I saw results like this. But I appreciate them more and more. It's still easy to find what you're looking for with a quick Ctrl+F. But there inevitably comes a time when I want to understand a concept deeper, and I can come back to results like this for the longer explanation.
I know that it doesn't have to be either a long explanation or a quick and concise snippet of information, it can be both. But I find that a lot of docs will either have long explanations or short snippets (because time is finite and doing both is duplicating efforts), and in those cases, I prefer the long explanation.
I would guess google A/B tested those results till python.org fell off the front page.
More to the point, I don't think either google or the people searching are wrong for that. The query isn't "teach me about python classes" it's "what is python __init__?".