It always puzzles me the hostility Mensa attracts. Is it the perceived elitism? What of any of the other high-IQ societies that exist? There are some that are even more selective in their entry requirements - for instance, Intertel is open to the top 1%, the Triple Nine Society is open to the top 0.1%, and the Prometheus society is only open to the top 0.003%. There's even the Mega Society which asks for the top 0.0001%.
Admittedly, yes, it is difficult to believe that intelligence can be measured on tests, but I wouldn't go as far as saying that there's no such thing as general intelligence.