Few years after forcing everyone to take their gold to the bank, the US president, Nixon in 1971 stopped everyone from having the right to convert their gold to fiat. Isn't that stealing? Government resent bitcoin because they can't control it like they did in 1971. Very soon, it will be illegal to own bitcoin in some countries, not because bitcoin is bad, but because bitcoin gives you the power to own your money. Bitcoin is more real than your money in the bank. Be your own bank by investing and learning about bitcoin.
https://www.federalreservehistory.org/essays/gold-convertibility-ends
Ironically the argument you use actually represents the opposite meaning. The gold standard was unsustainable and it would and would have stumped the standard of living all around the world, America especially. There simply isn't enough gold being dug out of the ground each year and it would have created a bubble in one commodity, affecting its practical usage. The government could actually very easily crash the price of Bitcoin and make it an undesirable asset by taking actions to ban it - wealthy people, institutions, investment banks and companies would run like hell from it at the first sign of trouble. To date they have been surprisingly lenient and it's nice to see them let it run so far, because the blockchain does seem like a useful ability to replace rather wasteful physical cash.