http://www.whatifsports.com/hd/GameResults/BoxScore.aspx?gid=12111271

Check this out. I know I am suppose to get defeated. His team was better than mine, I can live with this. My question is : how come he shoots .604... I never had any team shoot that high against my press team. I even went slow to counter his better athleticism...

Is my defense that bad?

To some degree it's fluke.  No your defense isn't that bad.  And you know that because your defense on average gives up less than 50% shooting per game.  But average means it doesn't have to always be around the exact number.  

2 things that could have contributed though.  1. He took a lot of free throws.  So it could just be that many of his misses you fouled, which doesn't count as a missed shot.  and 2. Because your team was in foul trouble some of your players, especially your big men, were very tired during the game, and he took advantage of that.  Thar going along with him having better team stamina and one extra eligible player, and your stamina being a little misleading since your walk-on has good stamina.

My passing from my guards and my low-post from my inside guys compliment each other really well. I was also able to get your players into foul trouble and then your players were tired while my players were still fresh. 

Fatigue is usually the answer to these type of questions.

Part of playing press means that some nights you're not going to be able to stop a shot to save your life.