At least, it does offer "some" legitimacy.
Judge Judy threw a case out once because both parties had colluded to try to avoid paying taxes, by marking the value of a car as $1 on the title of ownership, despite contrary proof that the transaction had been for several thousand dollars.
Then she said something like:
Taxes pay for this court. Taxes pay my salary. If you choose to make a contract that goes outside the law, don't expect the justice system to support that contract when something goes wrong. The same goes for drug dealers who have a drug deal go bad, or someone who knowingly buys stolen property.
Just imagine if a judge who doesn't like bitcoins, or just doesn't understand them, had said something similar about bitcoins. That would have set a precedent and that would have been a PR-nightmare for bitcoins. In a way, I also think it helped that the Federal US Marshalls repossessed bitcoins from the Silk Road a while back and resold them for 89 million dollars. By reselling bitcoins for its own benefit, the government made it an asset that you could more legitimately purchase and sell. After all, if you can legally buy this asset from the government at an auction, this means legitimate corporations can also buy and sell such assets, not just shady startups or shady people or potential terrorists.
On a side-note: It's not really true that taxes pay Judge Judy's salary, since she's making 47 millions this year for only 52 days of work. All that money comes from TV ads, not taxes. She's mostly an entertainer, not a normal judge, but her main point still remains regarding non-TV judges, most of those other judges get paid through taxes.