I don't think the author has a clue of what they are writing about...

"In this case, speed and efficiency have higher priority than human readability, therefore jQuery includes only essential features to keep the code tight and focused by using minimal variable and function names, minimal use of spaces, no comments, etc."

Someone mixing library purpose with minification process.

And I bet that all those infected scripts come from one infected website. They're not out there in the wild spreading through all jQuery installations and all jQuery plugins.