In practice some individuals do have immunity. If this case led the detectives to a local coffee shop do you really think they would have raided the owner's house at 6am and ransacked his home and business searching for something that they knew they were unlikely to find? It's not really that different from running a Tor exit node. The police knew that the traffic was likely coming from another source and that the most likely outcome was that the Tor node operator had no way of potentially knowing that anything illegal had even happened. How does that equate to probable cause to raid his house?
Yes, up until it comes to light that there is very little reason to believe that the owner is guilty. More importantly though they wouldn't handcuff him and trash his business when there's clearly no probable cause to do so.
ISPs have a specific set of statutes that grant them immunity as long as they comply with certain requirements [1]. Individual users do not.
[1] https://www.law.cornell.edu/uscode/text/18/2258B