where people at school afraid of eric and dylan?

it is well known how dylan used to harass girls in his gym class, as well as eric making threats to people on his website. with all this being said, why would the jocks pick on eric and dylan when they knew how quick to anger they were? did they just assume they wouldn’t snap one day? they made it very obvious that they had a lot of anger and hate towards the school, and people weren’t even that surprised when they learned eric was involved in the massacre.