Tainted coins = government dislikes history and will try to fight them in the future
I find this more accurate:
Tainting coins might be a pointless process of detecting actually illicit-related activity, but it's a very effective process of incentivizing bitcoin users to be as compliant and conformist as possible. Same as with anti-money laundering laws, and privacy sacrificing to protect from terrorism and tax evasion. In the end, it's an incentive of being meek, for the sake of the surveillance state.
I agree, government will become as hostile to crypto as it is useful to them to maximize power over the population. I expect Monero will be banned eventually. I don't see a Bitcoin ban in the US. The US will try to conquer Bitcoin with regulation and occasional imprisonments.
Governments around the world (not only US) will try to fight both. Monero is a red flag, no doubt. That doesn't mean there won't be any activity at all, though. It's a favorite option in decentralized exchanges, no wonder why. Lightning also makes transactions more private, so that will also be subjected sooner or later.