Usually copyright laws refer to a substantial part of a work, it maybe be 0.6% of the delivered web page, but it's 100% (presumably) of the article. The article counts separately as a work (and each image within an article could count as a separate work, there are conditions on that). But, in any case if all the textual context was copied that's still substantial. Interpreting things in a purely numerical way like that would be clearly ridiculous.

Such gotchas don't work in law in general (in my very limited experience).

Gotchas absolutely do work in this way in law. You just need to be willing to fight it in court.