Citizens United was 100% correct. No, the government should not be able to throw you in prison because you used money to publish a book criticizing the government.
It's interesting to me that one can look back at the effects that decision has had on the US and say it "was 100% correct."
It's a bit like sitting in the burning ruins of Rome and contemplating that Nero was 100% correct to focus on his music. I mean, I'm glad he got to do what he loves, but maybe 100% is just a tiny bit of an overstatement.
The court's job is to uphold the law. If you disagree with their interpretation, you can call them incorrect. If you have a problem with the consequences of the law, you have a problem with the legislature.
The above is true, but also: companies simply are not people, and they should not be supported above the individual, which was the consequences of that decision. Money is not the same as speech. treating it as such creates an aristocracy: something America as a country rebelled against during it's formation.
How so? If the answer is "Trump" I certainly won't disagree on the catastrophic part, but he didn't get elected because of money; in all three elections his campaign was substantially outspent by his opponents.
That is a major part of the reasoning for the Supreme Court rulings on the matter of corporate political funding.