That was pretty much my point. The screening may have change the location of the attack/tragedy but it didn't prevent the attack. At Disney, if you implemented a military base style screening where you screened anything and everything going into the park perimeter, you'd still have a ton of locations with large crowds that could be attacked.
Airport security is designed to prevent attacks on planes, not to make airports a safe location. Using that goal, the security worked in Brussels. If the goal of security at Disney was to prevent attacks inside the parks, you could possibly do that. You can't prevent all attacks on the property.
At the end of the day, does it matter if a terrorist detonates a bomb on Main Street during Wishes vs. detonating one at the monorail station with hoards of people crammed together waiting to leave after Wishes?