States have the ability to sue to block mergers as well as the federal government. See the recent 11 state lawsuit seeking to block the WarnerMount merger.
[1] https://viewfromthewing.com/passengers-demand-court-undo-ala...
https://www.hklaw.com/en/insights/publications/2017/10/futur...
It's probably the most inconsequential merger, from a consumer standpoint.
Video media sellers are dime a dozen these days, and the barrier to entry for selling video media is basically none. Warner brothers and paramount are nowhere near the only business to buy and watch media, and it affects almost no buyers negatively if they merge.