Just like public reviewers of products have to disclose that they got paid for the review. Madach if he took money that may influence an opinion he has to disclose it, Kol Shekein if he only has the “opinion” because he was paid he has to disclose it.
To Ezra’s credit though, one can argue that everyone knows he has no opinion of his own (since he is a PR hack) and there is no need to explicitly disclose that he got paid to write a piece to try and convince others.