It happened the other way round. Hive forked and froze Justin Sun's tokens on the Hive chain. So Justin Sun retaliated and froze the Hive developer tokens on the Steem chain.
So @blurtyield is right they're both the same. Important to note that Hive did the freezing of funds first. They also froze the funds of innocent bystanders like @steemchiller (of Steemworld stats) simply because he wouldn't take sides. Then said they'd let him in if he "apologised" - he didn't.
Hive has established a precedent of freezing coins not just for political reasons but for thought crime - poor steemchiller lost his coins for the crime of not saying anything. That's North-Korean style authoritarianism. Arguably worse than Steem.
That is incorrect. Justin Sun bought the ninja mine staked which was promised to the community for community funding. They froze the account to prevent ruining the platform by undelegating all the community projects (which he did). He then colluded with exchanged illegally to take user funds for governance to get his way. They then froze out his funds which shouldn't be his and put them in the DAO fund to be used as it was always intended and promised.
They only didn't airdrop funds to people who supported Justin and corrected any mistakes which happened to me. I was pretty vocal about it that I didn't respect that move but I get it. Justin Sun literally drained Steem from many accounts directly.
Also nothing stops Blurt from the same, it's the same infrastructure.