He's not asking Thomas to rule a certain way, so not bribery. Oliver isn't in court nor dodging a subpoena to be in court, so a contempt charge doesn't apply.

Of course the real reason for the offer is because Thomas has shown himself to be ethically compromised, refusing to recuse himself even when the case materially involves his wife and taking gifts (actual bribes) from a billionaire without either disclosing them or refusing himself from cases where that billionaire's interests are before the court.

Since asking nicely to follow judicial norms hasn't worked, just paying the guy to go away doesn't seem out of the question.

Or election meddling.