Again though, why is that someone who pulls a strike and screams any less able to defend themselves?

Someone on the forums a few years back posted a news story about a teenage girl from Denver who successfully defended herself from a man who tried to assault her.

There was of course the clips of the BBC reporter who defended himself against someone who was trying to attack him. Videos are still on YouTube.

Both of those incidents involved people who studied "light contact" karate if memory serves. I wonder sometimes if the idea that self defence = full contact training is more to do with machoism than any real understanding of the massive amount of variables that come in to play in self defence situations

A point could be made that arts like Kyokushin and Muay Thai generally employ a rock 'em sock 'em mentality where combatants simply stand toe to toe until one person falls over. The "bouncy bouncy" WKF style of karate or Olympic TKD employ a much more mobile approach to fighting, where a lot of emphasis is also on evasion of blows. What approach offers the best chance of not getting hit?
"Let your food be your medicine, and your medicine be your food" Hippocrates.