Just as people might be uncomfortable putting themselves forward, it might make them uncomfortable to be put up for election. They might be uncomfortable turning it down. Just as they might not put themselves up (because it's easier) they might not turn it down for the same reason if it were opt-out.

Being a moderator is not just a title you earn for being popular, it's an ongoing job that is often thankless. You should only be part of the election if that's something you want.

Just as people might be uncomfortable putting themselves forward, it might make them uncomfortable to be put up for election. They might be uncomfortable turning it down. They might remain in the running because it's the easier thing to do.

Being a moderator is not just a title you earn for being popular, it's an ongoing job that is often thankless and occasionally quite tough. You should only be part of the election if that's something you want.

But yes, by all means ask people to nominate themselves. If they want to run, they can.