You're not properly representing the large fraction of people who think the fine should be zero. It's kind of confusing unless you read it carefully, but 49% of people do not support fines at all. That pie chart you're copying only represents the other 51% of the population.

I mention that not to quibble with your formula, but because people seem to be seeing that chart and missing that part of the explanation.

In that case, it would be:

  0.51 * ((10+0)/2*0.32 + (100+11)/2*0.43 + (1000+101)/2*0.14 + (5000 + 1001)/2 * 0.03 + (100000+5001)/2*0.01 + (250000+100001)/2*0.01) 
  = $1,258.46