The subheadline laid it out.

Rep. Steve Cohen’s long career is evidence that the motive is partisan.

Which is a big so what. Partisan gerrymandering perhaps ought to be as illegal as racial gerrymandering, but it isn’t.

The editors partially addressed the so what at the end of their piece:

The Tennessee gerrymander is simply a GOP effort to divide a compact, populated area into multiple stringy districts for partisan gain, which is precisely what Democrats did in Virginia. It’s bad for competitive elections, but it isn’t racist.

The rest of this story is that there’s no “ought to be” IMNSHO regarding the legality of partisan gerrymandering. It’s a violation of the 14th Amendment’s requirement of equal protection of the laws. Competitive elections can occur only when that gerrymandering loophole is closed also.