So the solution is obvious. Mix 1 part brine with X parts seawater before releasing. Oceans are big, so X can be a very large number, if that is necessary.
As the article points out, desalinization produces "37.5 billion gallons (142 billion liters) of this salty-ass junk every day." What's your plan for pumping in X times that from the oceans, diluting it, and then pumping it out?
They're already pumping in 37.5B + 37.5*2.5/1.5B gallons of it, so pumping in a multiple of that is just a problem requiring money.
But getting the money to do so requires scaring the public into giving it to them, thus the scare articles like this one in the press.
Any problem of providing fresh water for human civilization is "just a problem requiring money." It's not like there is a lack of water on the Earth. So it's kind of silly to pick one single particular aspect (diluting brine) to try to hand-wave away as just a money problem.
In general, money is a significant constraint on engineering and can't be hand-waved away.
Also, why do you think that paper does not address the option of pumping in more ocean water and diluting it? (It's paywalled - if you'd like a PDF I can get you one.)