> In this case SA isn’t doing anything unlawful.
That's why the article is calling attention to the “140-year-old loophole” that is being exploited.
> If they want to disallow water to be diverted to farming, that’s one thing, but singling one entity in this whole deal seems to be odd.
They are singling out a federal grant from when the part of California involved was essentially uninhabited and the Colorado River wasn't heavily used that gives unlimited, no-usage-charge water to users in the particular locality where the Saudi farm is located.