It was explained to us that the judges felt that there was less than 5k of wind using sailor testimony (the 7 that filled for redress in a closed hearing), using times around the 2+ mile course, and based on the fact that the RC could not prove that there was in excess of 5 knots of breeze at all marks of the course. The rule reads:

race must have 5 knots of breeze at all marks of the course at the time of the start "as determined by the Race Committee".

Note that it doesn't say he has to prove it. It doesn't say he has to take readings at every mark using digital equipment. Note it doesn't say "as determined by the judges" or "as determined by the sailors". The Pro could lick his finger, stick it in the air, and start a race if he felt he had more than 5 knots and the breeze was consistent around the course. Also note that while he could not prove that there was more than 5 knots of wind at the start of the race, he could not prove there was less than 5. He did state that he felt that he had 5 knots or better based on the wind line that filled in and readings he had taken earlier. Also presented as evidence was readings from a Reynolds 33 moured just off the beach who had readings from 6k to 10k for the whole race. Also note that times around the course are irrelivant (even if you could accurately figure in chop and current effects) because the rule stated "at the start of a race". So basically the race was tossed because 7 teams felt there wasn't enough wind somehow they got three judges to side with them.