I cant be the only resposible parent that has a ...

I sense your frustration comes from that fact that you think that what you do should be sufficient to contain  your child. You are smarter than he, You need to act like it.

For example, if he gets thru the animal gate on the door, close the door and lock it. If you child is able to unlock it, install a double keyed dead bolt and lock it. This problem has been solved.

No you aren't the only parent with an escape artist for a child.  But there are a number of methods to prevent it or at least allow you to know when he does it. 

Your question took me right back to the Summer of 1997.  My daughter, Joanna, turned two that summer.  We were living in a very rural town of 700.  Joanna loved to get outside and see how far away she could get.  I was always reminding her older siblings not to leave the door open.  By mid-Spring, she could turn the doorknob, so we had to start locking the doors, too.  This one day, I was trying to cook dinner. I had put on a video and parked her right in front of it and locked both doors,expecting that to give me five minutes at a time to work, before checking on her.  A few minutes later, my doorbell rang.  When I opened it, I saw Joanna, naked, across the street, playing in a big mud puddle!  I knew she loved to be naked, and play in mud puddles.  What I didn't know was that she had figured out how to unlock the front door! 

So, if you're being accused of being a bad mother because your preschooler got outside of your house without your knowledge, know that you are not the only good mother it has happened to.  Actually, I doubt there are any parents who haven't EVER had a situation where they thought they knew where their child was and found out that they were really somewhere else.  I think it is a testimony to the existence of guardian angels that many of our children live long enough to grow up!