It is statement that I've heard several times in academia, but am still a bit puzzled at how it was reached.
This is unfortunately something almost everyone is guilty of (LGBT activists included). Once you politicise an issue, people begin to twist the facts, misrepresent data and select evidence that is perceived as supporting their own view point, while tossing aside evidence that contradicts it. Everyone wants "the science" to come out in their favor.
It is easy to find conflicting stats because sometimes the definition used is self-identifying homosexuals, people asked if they are MSM, or physical arousal tests. The self-identified definitions are all part-right, since self-identification is disincentivized, but for the sake of science the clearest definition, and one of the smallest estimations, is probably the one we'll see used.
TLDR: responses vary widely depending on the survey method used. IMO, the higher numbers are more believable because there are subjectively tons of skittish gay dudes.
This was the survey done in the Netherlands a few years ago: https://en.wikipedia.org/wiki/Demographics_of_sexual_orienta...
NL is a very liberal, small and tolerant society - thus is a much better sample than the US (where being gay may still not be looked upon favorably by a large part of the population).
Even if most people there support gay rights, many men can still be closeted.
Can you offer specific issues with that survey? The general "i think there are probably more closeted gay men out there' we can dispense with as that's a non-falsifiable statement.
I specifically picked Netherlands as they are as liberal a society you can have with regards to gay lifestyle as you will find on this planet, the survey was done online and had a large sample size (30k people).
Plenty of reason not to volunteer information about yourself even in the most liberal of societies.