Re: The IRS. No, not pro evading laws. Like any law enforcement office, they can overreach, overstate, misinterpret, conflate, etc. Restricting their access has pros for innocents.
Here's a real example. Aluminum extrudes are highly import taxed UNLESS they are are an integral product feature. Does the IRS get to see my emails on that, pre-emptively, before any presumption of doubt? Should they be able to poke a few search terms into an NSA database? Or is the burden on them to get a subpoena?
I see no weirdness that they can see my books but have no business in my conversations. Decades ago, they couldn't peer into meetings in a real-time, prior reasonable doubt way. 1984 and all.