Here's an economic concept: the market places a 10% premium on freshly minted zero-taint BTC over 'gently used' coins. Good luck with your stolen Evolution coins!
Bitcoin doesn't meet the highest 'can't be evil' / 'can't be non-fungible' technical standard because the code may be modified with black/white/grey/red lists of forbidden/allowed coins/taints.
So no need to even get into the more significant (but more general issue) of socioeconomic interchangeability.
Collectors pay a premium for weird things. That doesn't mean that bitcoin is not fungible.
With respect to fiat, collectors have paid millions of dollars for nickels. So that doesn't change anything about fiat's fungibility.
true but just having one example of where a business/site/exchange/merchant not accepting certain bitcoins coming from certain addresses linked to a theft breaks bitcoin's fungibility in my view.