I'm sure Breitbart is blindly trumpeting the tax cut, just without the profiles/statistics showing what types of people it helps. There's a reason these outlets are showing "typical" families making $250k. That's how they can show that "typical" families benefit significantly.
Most news outlets also stand to benefit significantly because it is primarily a tax cut for businesses.
Here are the current headline on their front page which mention 'tax cut'. "Trump: Patriots Owner Robert Kraft Building Factory in N. Carolina After Tax Cut Bill", "Bank of America Paying $1,000 Tax Cut Bonuses to 145,000 American Workers", "Ted Lieu: Tax Cuts Make Poor People Jealous", "WINNING: Germans Fear Job Losses from U.S. Tax Cuts…", "‘Avengers’ Director Joss Whedon Has Two-Day Twitter Meltdown Over Trump, GOP Tax Cut Vote", "Winning: President Donald Trump Signs Historic Tax Cut Bill".
Put "typical family" into the Breitbart search box.
The first match is for http://www.breitbart.com/economics/2017/09/30/mainstream-med... . In it, "Gary Cohn, the White House’s chief economic adviser and its lead advocate for the GOP tax overhaul" talked about the effect of the then-tax plan on "a typical family earning $100,000 with two children that has been a standard deducter, has used the standard deduction and continues to use the standard deduction".
(You'll notice that Cohn used $100,000 of income, which is the same income that Texas Sen. John Cornyn was quoted as tweeting.)
Other media sources misinterpreted that as saying that the typical family earns $100,000, when "the average American family makes $74,000 a year".
Breitbart's article complained about "the difficulty of persuading a skeptical mainstream media that the proposal would cut taxes for the middle class."
I found no article describing how the tax cut would benefit the typical family.
I think there's also the "I haven't made it yet, but I'll get there" mindset of a lot of readers. If someone hopes to be making $250k someday, then being assured that when they do they won't be penalized for it is reassuring.
Most news outlets also stand to benefit significantly because it is primarily a tax cut for businesses.