If not, where’s the line? Citizens United was a case about a relatively narrow question, and the opinion was well reasoned. I believe it was correct. If you think it was wrongly decided, where’s the flaw in its logic?
The second thing, giving special favors to people who helped you get elected, can be corruption, whether or not money is involved, as long as a quid pro quo arrangement can be shown. For example, few people would disagree that its core free speech for newspapers to be able to endorse candidates. (Even the government in Citizens United suggested that the freedom of the press clause might protect newspapers separately from general speech protections.) But if the Washington Post entered into a quid pro quo arrangement with Joe Biden to endorse him in return for favorable legislation that specifically benefited the newspaper, that might be prosecuted as a corrupt quid pro quo arrangement even though no money changed hands. The quid pro quo arrangement in your hypothetical--which Citizens United does not address--is what makes the corruption, not spending money to get someone elected.
Do you have an argument that would be persuasive to someone who didn't think the entire concept of a market economy leads inexorably to political corruption?
He doesn't keep the title, but otherwise he keeps the boat. It's in his slip, it's maintained by his crew (well a company he pays to crew it). That's how it is, today. You can see this in harbors around the US.
The public is in the EXACT same denial about the politicians reading the laws they pass. It's fantasy to think that the corruption isn't blatant.
How does that translate into the politician getting the boat?