I don't think it should be made easy, or the default, or that killfiles be easily shared -- such as by being global.
It's like this Steakhouse I used to go to. NO condiments on the table, and the chef/owner would come out and publicly berate you and ask you never to come back if you so much as asked for them.
To my mind, extensive use of killfiles would destroy the flavor of the Free Republic steak.