Using classic Outlook for Windows in business environments
If those messages are arriving in the Junk Email folder, they're already considered blocked. You can't prevent the delivery, only control the destination folder. Also, rules work only for the Inbox. It's pointless to create rules for messages delivered to the Junk Email folder because the junk filter runs before the rules engine.
If you don't want to know what the junk messages contain, don't look at them. They'll be deleted automatically after 10 to 30 days.