can't be boxed in one category. It's meaning isn't the same from one govt to another. Wouldn't it start a different trouble if taint free UTXOs were rejected for being naughty by zkSNACKs but a few govts declared them taint free?
Then that's why, layer your mixing/tumbling with other centralized mixers, then the Lightning Network, then back to onchain, then make attempts to mix them further in Wasabi's CoinJoin/centralized coordinator in order to get that "clean, safe, government-approved" UTXOs that are free from "taint".
Except the fact that you aren't getting that. There is no standard to measure and determine made up taint. Governments don't like the pursuit of privacy, so you can't use government-approved and taint-free UTXOs in the same sentence as mixing or coinjoining. Additionally, coins from mixers and coinjoins may trigger alarms on some services and not on others, proving again that they are making up their definitions of taint as they go.