Without default privacy, it is easy to separate non private from private users and discriminate them by considering private users money launderers or terrorist funders.
If a government wanted to discriminate it wouldn't make any difference if your coins were mixed or not. They could even do it for virgin coins (freshly created coins in a coinbase transaction, ie. the block reward).
Deposit your mixed coins on a Centralized Exchange and you will be asked for documents. Deposit Monero instead and they will probably not.
Same thing here. The centralized place could be under pressure by government to make anon coins (such as Monero) illegal and anybody who has ever deposited these coins in their account in the past would be under discrimination.
The solution to problems you are describing is not changing bitcoin protocol that is working fine and is providing enough privacy. The solution is avoiding centralization and petitioning your government about their unreasonable laws.