I think my analogy is better. Yours if a physical object so UPS has a need to know if it could be hazardous. I suppose a virus could be in an email, so they have a right to make sure it doesn’t contain any, but you should still have a reasonable expectation of privacy about the content. New tech presents new problems, but the principle should be the same. And whether the ISP can give your content to a third party is yet another issue. But I thought what he wrote about was NSA metadata collection, which isn’t given by the ISP, just scooped up directly by the government.
Like I said though it’s not enough not to confirm. It’s one issue, and there will be other good justices to help him see the light on this, IMHO.
We are NOT talking about content. Meta data is the outside information, not the inside information. We are also NOT talking about ISPs, rather cell phone carriers. What is collected is source phone number, destination phone number, length of the call - the information needed to make the connection.