all of the venture capitalists who invested in oracle became successful, not just the one who was married to a congressperson.

Sure, but this one then became much richer than he already was through marrying a congresperson who consistently outperforms the market herself in spite of having no background in stock trading prior to achieving various political posts that inherently bring inside information.

I'm not sure capitalism+marriage makes it an extra level of evil

Capatilism+exploiting your marriage with a corrupt politician for unfair financial gain or BEING that endlessly corrupt politician, on the other hand..