I may sound like a total noob or dumbass, but, isn't cash held in your hand anonymous?
Cash would be generally anonymous if you had a bundle of 10's of something, i.e. USD Fiat
and not even reporting where that came from and you spent it on the local drug dealer or
c-store. Who's to know who the hell you are when using cash instead of debit/credit?
Supply of cash is control by governments and banks. They dont control bitcoin though. Thus its seems that "anonymity" is only excuse for them to squash something out of their control.
When there is literally no other reason for them to be against it, they will go for absolutely anything they can. Since Bitcoin is overall "good" in its other aspects, they can only target the anonymity offered by it.
There is no other "bad" aspect to Bitcoin, at least aspects that affect the government.