I know exactly how I feel about this: Gross!

Telling someone that's interviewing "you should come to burning man because my wife and I are swingers" is gross and inappropriate (borderline illegal?).

If you're inclined to ask someone who you were interviewing for a job to come do sex to you and your wife, I think it's a very reasonable expectation that you confirm this person is aware they have not gotten the job. Doubly so when you're an executive of one of the largest companies in the world. Seems like this is extremely poor judgement at best, and abuse of his position/the implication of a job at worst.