Of course politicians are pro-money. You don't get to be a politician in a capitalist country without being pro-money, wealthy, and well connected to others who are wealthy.
Bribery is in most cases legal in the US. It's called lobbying, or campaign donations, or the revolving door between public service and private industry. It's also an unsolvable problem given the current economic paradigm. The capitalist class will determine government policy in one way or another, as the government is designed to protect the interests of the capitalist class. The will of the working people is completely irrelevant.
Russian money, insofar as it does exist in US politics (there's astonishingly little of it compared to other sources) is drawn to attention by a media that is owned by the same companies and people that are bribing in a much larger way. They call attention to the few thousand dollars a Russian immigrant may or may not have donated to the NRA or a Republican candidate to distract from the billions of dollars Wall Street spends on candidates and kickbacks to make sure they're the ones who control US economic, financial, and foreign policy. It's easy to call attention to Russian money because the same media has created an environment in which anything Russian is pure evil, so people don't even question the content of the story being told. This has its roots in Cold War anti-Soviet propaganda, which has been dug up and repackaged to use against a post-2008 "non-aligned" modern Russia.