You can always blame the monarchy for perpetuating the monarchy. “They didn’t, as a whole, proactively reject our bullshit” doesn’t mean they have to keep doing the bullshit. Everyone has agency, stop pretending one of the richest and most privileged people in the world just doesn’t have any other choice.

He doesn’t have to abdicate, he can just stop pretending he’s special. Tell them “no thank you, I don’t think my role as king of a colony is appropriate”. Let’s see that democracy you think loves monarchy pass a measure to depose an absent king and choose a successor. The monarchy exists because people are lazy and just let it keep existing, not because they’re deeply devoted to maintaining this dumb farce. But he’s not going to do that, not because he cares about democracy, but because he believes he’s special and is happy to tour “his” colonies.