Can and should the federal government force all 50 states to allow straight ticket voting?

[FrodosPet]

12. From the opinion of the original court, not allowing straight ticket voting is racist

http://www.politico.com/f/?id=00000156-9930-d2af-af76-9bb77f150001

The district court concluded that the plaintiffs had demonstrated that PA 268 imposed a
disproportionate effect on African-American voters because the Metzger report “demonstrated
that African-Americans are more likely to use straight-party voting than white voters, and ‘its
elimination will disproportionately affect African-American voters.’” 2016 WL 3922355, at *10
(quoting R. 1-10 (Metzger Report at 1) (Page ID #220)). The district court further found that this
burden was “linked to ‘social and historical conditions’ that have or currently produce
discrimination against members of the protected class,’” citing Gingles factors 2, 5, 6, 7, 8, and 9
as relevant. Id. at *13. The district court drew from available news articles and facts from
Metzger’s report that demonstrated that African Americans in Michigan “tend to vote
overwhelmingly for Democrats,” that African Americans “continue to bear the harmful effects of
past discrimination,” and that “[r]ecent political campaigns in Michigan . . . have been marred
with direct and indirect racial appeals.” Id. at *11–13

Why are the citizens of the 40 states which do not allow straight party voting not afforded the same protection of their right to vote in a manner they choose and are comfortable with?

We need 50 state straight-ticket voting.