How many thousand of answers did you get?
If you didn't contact all the people who responded to your offer I am wondering on what criteria you based your final decision? The first to respond? The most friendly message? The best username (avatar)?
I am not saying you didn't choose the best offer but if you did then it would seem that it is very much down to luck. TBH I wasn't expecting to get the assignment but I was expecting to at least be given a fair chance to get it.