Just seen the poll results showing that most people are going for 80-100%. Seems a bit harsh to me.
In terms of apparent intelligence I think the board reflects real life quite well. There are a small proportion of idiots a lot in the middle ground a some who are obviously quite bright. Although on an internet forum everyone gets an equal opportunity to get themselves heard so the idiots can be quite noticable.
In terms of trading ability everyone has to start somewhere and here is a better place than most. Over 95% of traders can't make money anyway so if you factor in all the newbies and the fact that most here are retail/spreadbetters then obviously the proportion of good traders will be very small. However you cannot say that someone is a retard because they don't make money trading or even have much trading experience or knowledge.
That said it always amazes generally in trading me to see how many obviously intelligent people make the same mistakes over and over. Also how few look beyond the generally accepted lore of trading passed on by authors, internet gurus etc despite the fact that these people in all probability don't make their living from the markets themselves.