Blažek gate clearly shows that tainted Bitcoin is valued differently than non-tainted Bitcoin. This is going to be a new standard. Is your BTC pure or tainted? New or mature? Involved in one utxo or a million? KYCed or not? All that will effect the final price... And there will be parallel markets and exchanges for every combination.
Discussion
I very much doubt this. In such case, governments would not be able to sell confiscated BTC which they currently happily do.
Government will be cleaning the Bitcoin. Anything coming from a state institution will be automatically untainted... They would be the ones setting up the rules.