So, judging from your post you’ve demonstrated that you:

• Have a steady job (proved by a letter from your employer)
• Prior travel experience in the U.S and you did return (which means you were not looking to stay)
• Your wife and your baby that hasn’t turned a year yet!
• An official invitation to attend an event

And all this wasn’t enough to prove that you were not planning on running off first thing you landed in this cold country? They openly admitted that they did not believe you and thought you might stay. Well, in this case, I wonder what is the siffucient proof for those polite american juniors that you are planning to return? Two houses and a thriving business? I believe a human factor played into it, and an officer who was handling your application should be held responsible!

Thanks for your post, it was a nice read!