It's the government trying to enforce their opinion of who should own those Bitcoins, thereby taking power away from the owner that the network has decided on, which would be "whoever has the cryptographic keys".
A person can believe whatever they want, but when push comes to shove, it's a country's court of law that ultimately determines who legally owns what.
I think you've answered your own question - a true crypto believer does not agree with that. If the smart contract says the Ethereum is mine because you wrote it poorly and I called the transfer money function in the right way ("exploited it"), a true believer would say "yep, it's yours."
In that world, there is no such thing as stealing. If the crypto transfered, it was allowed to transfer by the contract.
The part that "true believers" are meant to hate is that now, someone on one side of the contract is grasping back to Money 1.0 concepts of conceptual ownership and meeting-of-the-minds type contracts. This enforcement action shows that the government thinks of Ethereum et al in this way too. And therefore the crypto paradise dream is dead.