first off, if the gifts are disclosed and the recipients recuse if necessary then the recipients have a safe harbor from discipline.
I believe the piece you linked to uses disclosures to do its research.
Of course out Justice Thomas often did not disclose so it took journalists to reveal it. And my memory is that he did not recuse when he should have.
When you don't disclose and you repeatedly take hundreds of thousands of dollars of gifts from highly charged political people you deserve being called corrupt.