Right. It’s not “corrupt” to have done it.

Is there a difference between an article you paid someone to write about you and one that was written without your involvement? Yes. There is.

Would this article have existed at all had he not paid for it? Possible, but doubtful.

Wikipedia is not editorial journalism, it is an encyclopedia. His inclusion in said encyclopedia was paid sponsorship. An ad. Wikipedia’s policies don’t require it to be said on the page itself, which is a shame, because knowing whether the subject of an article paid for it to exist does change the reader’s perception of the article. It absolutely does.