As I said, one way or another, one chain (fork) will survive. Users on the other chain may scream bloody murder, but arguing with math will get you nowhere.
Yes and if sufficiently mixed, you can't try appease those who want the bad fork, because you can't extract their transactions from the bad fork and put into the good fork.
And this is the qualitative threat difference from block chains that don't mix transactions.
Except that all chains have mechanisms of mixes, maybe not on chain, but good luck untangling any block chain after any significant period of time, once people have traded through exchanges (many that are effectively totally anonymous), used coin mixers, used coins to rent rigs and mine new coins, etc. You can probably do it for a small number of blocks, just as a fork of around 40 blocks caused no lasting trouble for Monero last month. But after hours or days, any chain is equally intractable to undo.
Furthermore I'm not convinced even if it could be done, that it would be helpful to users. Fungibility might very well be more valuable than the ability to pick winners and losers after an incident.