Yes you should throw in common sense
Common sense is something that our intuition tells us is true, even though we can't articulate why exactly it's true. Therefore, a poor substitute for facts. Now when the facts and your common sense tell you things that contradict each other, maybe you need to step back and ask yourself if you're misreading the facts. But if they tell you the same thing then it's better to rely on the facts. They're generally more convincing when you're trying to persuade someone to agree with your version of the story.
U.S. News is not data at all.
Actually, it is data because there's actually a methodology there that they use to come up with their numbers. You can argue about the quality of their methodology and whether it actually leads to useful conclusions, but you can't argue that it's actual data.
they do give bar passage rate a whopping 2% consideration in the rankings.
Here for example, you're not arguing that the bar passage data is not data; you're just arguing about their methodology, i.e. you think it should be worth more than 2%. That's different from saying it's not data.
And as I've said elsewhere, bar passage isn't all that relevant in terms of ranking schools at the very top, because they're not trying to teach people how to pass the bar, and year-to-year variations in their bar passage rate relative to each other don't really reflect year-to-year variation in their quality relative to each other. Maybe for law schools that aren't at the very top level it would make sense to weigh bar passage more heavily, but at the top ten schools they just expect you to learn all that stuff the month or two before the bar.
other measurements are completely subjective and based on unidentified people.
People's opinions are subjective, that's true. On the other hand, when you aggregate a large number of opinions on the relative value of something, you're probably going to get something close to the actual value of the thing. Or so says the theory behind the stock market, anyway.
You are correct that they need to give a better idea of whom they're asking though.
Then acceptance and placement rates are so blatantly tweeked by every school that it is not even worth mentioning.
Every school, really? Aren't you just generalizing based on some anecdotes you've heard? You think that Harvard and Yale are tweaking their placement numbers?
You should use your common sense when picking a school, if you your choices are between Stanford and Williamette go to Stanford.
The only reason why this works, as I've explained before, is because common sense and the data both point in the same direction: Stanford is superior to Williamette on most measures, so the data tells you the same thing that your common sense does. In your other example, there was some data indicating that the transfer made sense, i.e. the destination school's higher ranking, but on the other hand there was probably also data arguing against the transfer, i.e. a minimal difference in terms of job placement.