That poll has 500 respondents.
Over 1,000,000 folks have participated in EA.
It represents the thoughts of less than 0.05 % of the community.
Most polls supposed to approximate global reality have a seamless percentage, or even inferior.
A representative sample size, by it's very nature, must be representative of the overall population.
Sure, no one would argue the forums of evidence we have are perfect but they are what we have available to us and making conclusions on the basis of evidence is better than coming to conclusions without evidence.