Whenever I read something like this I look my access and sshd logs for abuse IPs and check if they are Tor exit nodes. The Tor traffic is always negligible like 100 failed ssh logins out of 170k are from Tor exit nodes. Or 670 out of 400k for my nginx access.log. Am I unique and everyone else sees vastly different numbers where blocking Tor exits makes a significant difference in the abuse they get?