I'd be willing to wager my life on the fact that the government, any government, lacks the ability, resource, and desire to muster the compute power necessary to reverse a single bitcoin transaction more than a few hours old.

The government doesn't need to waste time manipulating blockchains. They can simply seize your assets by force.

Our government can't even stop people from distributing files containing data they don't like - what makes you think they can magically seize every single copy of a wallet that exists?

only if you let them.

An address could be kept anonymous with good op-sec. If you know that your actions are going to attract the ire of some people with guns, you will practise op-sec.

Whatever you say Mr. Secret Agent Man. I'm sure you're a real expert on "op-sec", much better than the FBI or Treasury Department.

Because government agencies would never mislead the public as to the nature and capabilities of their technical offensive capability?