Are event hooks breakable or not?

The event hooks are made out of girders just like the basement hooks, instead of flimsier materials. So I guess this means they are unbreakable? But then the event hooks still break when a survivor is sacrificed. So the girders don’t mean they’re unbreakable? It’s just confusing. The basement hooks should be made out of girders showing they’re more sturdy and can’t be broken. While event hooks should just be reinforced by the entity, so once they are able to be broken the entity bracing would disappear. (Event hooks should become breakable after killer gets points from first unhook. Aka breakdown should work as intended.)