No it would not be. Rational would be realizing that NO driver is expecting or looking for a person walking on the track.
That's not entirely true. The whole point of a caution flag is for drivers to slow down and look for just such an occurrence. Emergency crews rely on the drivers NOT running over them while they're trying to clear a wreck. Which in no way excuses the stupidity of Ward marching down the track, into traffic, basically throwing a fit.
While I agree - it's not rational to assume it was intentional - Stewart should have been more careful, and regardless of what statements he's made, I promise you he's thinking the same thing about now.
What specifically should Stewart have done to have been more careful? This is not too hard to answer using hindsight. However, it's much more difficult to do before shit like this happens.
Of course. My guess is Stewart knew that Ward was grandstanding and thought it would be cute to throw some dirt on him. He just didn't expect him to be standing in the middle of the track.
There was ample stupidity on both sides of this - even stupidity on the part of the racing community for passively encouraging this kind of behavior. Hopefully it will be a wake up call.