Really? Doctors measured every single male in the country? Doubtful. Show me, please.
Spurious argument.
You do not have to measure every man to arrive at a statistically valid result.
If you properly randomize a study, you can arrive at accurate estimates for an entire population, and this is verified by the fact that results do not change regardless of the size of the sampled population.
In other words, if measuring 500 men, properly randomized ,gives you a 2.5% result...
And measuring 5000 men gives you the same result. And measuring 50,000 men gives you the same result.... then you can be assured that measuring 50 million will give the same result.
That is how polling works... There is always a margin for error, but that is usually only 2-4% So, even allowing for the worst likely error, that puts the number of above 7 inch men at around 6.5%
( properly randomized would mean taking into account normal demographics... your results might differ if the sample is unusually heavy in asian males, or some other ethnic groups. But that is why any poll must have proper methodology )