Eh, the principle might be good (though it's not odd that not everyone shares the same principles), but one can hold it and still have exceptions. For example, what about a governmental institution or a public company¹? What about a semi-public company, like a monopolist utility? What if the uploader of the data is OK with it, but the site hoster prevents it?
¹ in the sense of owned by the State, not listed on the stock market
I'm not saying there aren't legitimate reasons for writing scrapers. I've written plenty myself. It was just odd to see this disregarded entirely.
As for the commonality of principles, game theory explains most of them, so it isn't more surprising than that we all work with the same prime numbers, say. A simple principle of reciprocity will produce something along the lines of "respect other people's wishes".
I can't say I agree. I mean, a serious, interesting essay can certainly be written on the ethics of scraping. But these short preludes on technical posts just end up sounding either like a disingenuous legal disclaimer or a preachy paternalistic tirade.
¹ in the sense of owned by the State, not listed on the stock market