Any service that offers web server access, is automatically less secure than my private firewalled computer. (assuming I don't install trojan/viruses myself).
This proves you don't understand network security.
Reality:
When comparing your computer connected to the WAN to a server connected to the WAN they are both as secure as they are designed to be. "automatically" doesn't even enter into the discussion.
Most servers are locked down far more than either OSX or Windows OS's even with firewalls. They have to be as they are more valuable targets.
Most Bitcoin hot wallet "hacker attacks" are likely inside jobs where outside hackers are blamed for internal theft.