Being in receipt of tax revenue is no measure of being a useful department. And how does it work when other countries are found spying on the US or UK? presumably this is also perfectly acceptable.
Well, yeah. If the U.S. was that concerned about spying as a rule, we wouldn't treat with Israel, China or Russia... ever. Undoubtedly there are other nations with an interest in U.S. secrets that simply don't hit the news that often.