Sure. And so has the IRS, which “persuaded a federal judge”, according to the article.

I guess they thought it was a reasonable request to get the data of the 25,000 US citizens who made significant profit with bitcoin in those years, when only a few hundred reported such earnings in total.

That's an estimate at best. How many if tbise who profitted actually cashed out?

It's not just a matter of tracking those that cashed out as taxes are on the net profits of individual trades. Even converting between coins (ex: sell BTC, buy ETH) is a taxable event.

Cross-referencing a public ledger is not an illegal search.

The 4th amendment does not prevent combing through public data (the blockchain), nor does it prevent going through due process to obtain data (the coinbase order).