I believe deplatforming of flat earthers is already happening. Anyone who holds that position is not allowed on television and not allowed to run national tv ads and wouldn't be allowed to teach.
Free speech is a concept that exists outside of the US.
Free speech is about being able to express ideas and these can be supressed by private entities, communities or a number of non-government entities like a church.
I don't think it is wise because whoever is in power will change fringe groups who need to be censored. Today it's the far right, during wwii it was anyone from Japan tomorrow it could be blm or women with tails. The one thing we know is it will change.
What's important is to being as open as possible and having open structures.
All of these are education problems not free speech problems. Speech is a signal not something to be repressed
Australia is part of the 5 eyes alliance which automatically shares data between the US/Canada/UK/New Zealand which means it is a safe bet that the US can get this data as easily as it would be on it's own soil.
As an American storing data in Australia creates another problem. The US can't spy in the US on it's own citizens but another country can at the request of the US government and will report everything back to the US.
I would pick Russia or China first...
Or just use protonmail which is designed to offer some protection.
I'm sure they could watch a few known wallets but how do they watch everyone globally while identifying and connecting Americans? Now throw in different kind of coins and what you are assuming is possible is not possible.
That would cover users who are poor at managing software. Being able to turn them off would require someone to be good at managing software. Why remove control from those users?
Most people who are idiots are not terrorists either.
On average a terrorist would be smarter than the average person. Terrorists are highly motiviated individuals, they can deeply understand an ideology and they activity learn/train in specialized skills. Compared to the average person their IQ would be 20 points higher.
Being a terrorist isn't easy. It's not a job for everyone.