Because you block legitimate visitors. After we ran out of IPv4 space and started to use CGNAT instead of IPv6, the internet has become a bastardized version of itself.
edit: That isn't to say they should be logging every packet... But if I work for XYZ Hosting Company and spin up a new VM, hand you the IP, and you turn the IP into a mini-shodan scanner... Is the hosting company at least a little responsible for what happens next?