So because Kavanaugh will follow the law of the land (Constitution) and require that if you want to legislate, you have to do it through the legislature (not through a court of Oligarchs), the left is losing their minds. Some examples included.
- NYT - NYT had a snotty tone when intro'ing Brett Kavanaugh's and his record of "diversity". They mentioning the Women, and omitted the other minorities: 6 Asian Americans, 5 African American, and 2 Hispanics. They also omitted that Nefarious RBG has a far worse record for diversity, as that's the bar they would compare everyone to.
- NBC (reporter Leigh Ann Caldwell) invented a narrative that Kavanaugh was picked because of a backroom deal that Trump and Justice Kennedy made -- that Kennedy would retire if Trump picked Kavanaugh. It's an absurd conspiracy theory, and when even other far left stations started questioning it, they walked it back and admitted it likely didn't happen and they had no evidence to support their claim that it had.  Of course Hollywood liberals, all jumped and outraged at the FakeNews story.
- ABC had prewarmed their outrage-machine engines, hours before the pick, by pre-announcing tonights coverage of "controversial" pick, hours before the pick was made.  Which goes to show they were prepared to be outraged, no matter who was picked.
- CNN first warned that Trump would pick Judge Amy Coney Barrett because she was a woman, and so they started denigrating her in a campaign to undermine the eventual pick (like saying it was just because of her looks, etc). Then when Trump surprised them by going with Kavanaugh, they shifted to claiming it was a sexist snub to not have picked her. This was by the same person (Chris Cuomo) who had defended against the claim that CNN was an “anti-Trump” news media outlet.  Sure, because damned if he picks her, damned if he doesn't, is what fair and balanced looks like to CNN.
Then CNN went on to claim that because Kavanaugh has aligned with the majority of the court before on whether Presidents should be shielded from Litigation while serving, that this is why Trump picked him. (As if one justices opinion mattered).  They also do a lot of hand-waiving on Roe and Abortion -- but judges aren't supposed to rule on that, and they have nothing to back up their claims, or they would have put it in the article.
- Gabby Giffords’ statement sums it up, "“In nominating Judge Kavanaugh to be the next Supreme Court justice, the Trump Administration is once again showing brazen disregard for the people it claims to protect. Judge Kavanaugh’s dangerous views on the Second Amendment are far outside the mainstream of even conservative thought and stand in direct opposition to the values and priorities of the vast majority of Americans." What are the views that are so outside the mainstream? That he sided with multiple prior Supreme Court rulings that upheld that the right to bear arms is an individual right, and that you can't outlaw guns just because they have decorator parts that make them look scarier to the uninformed.
- Elizabeth Warren showed up to an impromptu and spontaenous protest, with a pre-printed script that she read from. 
- Kirsten Gillibrand (NY Senator) promised to stand by her pledge to violate her oath of office and the Constitution, by blocking any appointment by Trump (until after the election). 
- Chuck Schumer followed suit, vowing to oppose Kavanaugh's nomination "with everything I have," and of course lots of hand-wavey stuff about Women's reproductive rights, and so on. Either he doesn't know what's the difference between the Judiciary and Legislature, or he's hope his gullible base doesn't.
- Bernie Sanders promised, "Nothing is more important now than doing everything in our power to stop the nomination of Brett Kavanaugh to the Supreme Court". Um, why? Never mind, a cranky millionaire socialists view of the Constitution isn't worth entertaining.
- Five Democratic senators and Judiciary Committee ranking members were invited to the nomination announcement. In a show of bipartisan good faith and approaching this in an open and unbiased manner, all five declined: Dianne Feinstein (CA), Joe Donnelly (In), Doug Jones (Al), Heidi Heitkamp (ND), Joe Manchin (WV).
- Hollywood took it about how you'd expect a bunch of tantruming High School Drop-out and other drama queens might. The Constitution sucks, you suck, I'm going to fling dirt and pout. 
There were immediate pre-planned, "spontaneous" astroturf protests against the pick. With entire sets of pre-printed signs ready to go -- so no matter which of the 5 finalists was chosen, there could be equal outrage. But they were hostile, caustic, and FoxNews' Shannon Bream decided to flee the threatening place, rather than risk injury to crew. 
Their attacks on him cover a spectrum of reasons why he isn't qualified: his name is Brett, he drank beer in college, he likes baseball and bought season tickets once, he has two daughters, he might not vote how they want (he's a textualist that respects the Constitution as written), he's a white male, he will kill people (seriously), and while the media is OK calling Ivanka Trump a feckless cunt, Kavanaugh may have once mouthed the word "bitch" to Hillary Clinton (according to a single anti-conservative and anonymous source). Wow, how could anyone get on the Supreme Court with such a dastardly record of being normal? 
The conservatives are over the moon with the pick, and Kavanaugh's "Gold Plated Résumé. Black Leaders applaud Kavanaugh's nomination As Mitt Romney said, "Esteemed by his colleagues, faithful to the Constitution, a record of thoughtful decisions, and already confirmed for the DC Circuit; Brett Kavanaugh has the right stuff." Even the New York Times (Akhil Amar) wrote "A Liberal's Case for Brett Kavanaugh", which agreed with Trump's assessment that Kavanaugh is "someone with impeccable credentials, great intellect, unbiased judgment, and deep reverence for the laws and Constitution of the United States.” But Liberal's don't rule the DNC, the Progressives and Socialists do.
When Kavanaugh was approved to the federal bench back in 2006, it was during one of the Democrats many fits of blocking all Conservative Judges for years. (3 years in Kavanaugh's case). Basically, this was just a tantrum that he was being appointed by Bush -- but he was finally approved 57-36. The Democrats later complained when the Republicans slow-rolled some of the Democrat judicial appointments for Obama, as a tit-for-tat play -- but since the Democrats have no memories for their bad behavior (and the media won't hold them accountable for it), they forgot why that happened.