Spitting blockchain into two happens all the time. I think there are four Bitcoins chains and three Ethereum chains by now.

Those new chains always took new names and applied to exchanges to be added under those new names. Effectively doubling the coin for each user. Normal thing to do.

Confiscating coins is not something not at all normal. Confiscating is setting a bad precedence.

If Steem really wanted to get rid of the users they should have powered the accounts down, blocked them from power up.

And yet, Hive should have gone that route as well: Forced power down instead of airdrop exclusion.