You're assuming the (male) population groups itself roughly evenly into those three camps, when absent outside information it's just as reasonable to assume that the population splits itself up closer to the distribution seen in the study.
It's unreasonable to assume it is exactly equally split yes. But in a culture as highly politically charged as the present day US it isn't unreasonable to assume that political affiliation affects your social prospects and the differences aren't purely population effects.
It's open to whatever they decided to use to determine the affiliations when that stat was determined, because social "sciences" are bullshit with no real standards. But at least for data I've seen that uses registered rep, dem, or none/independent as a proxy (not ideal, but at least it's objective), men under 30 are pretty consistently >30% none/ind.
You're assuming the (male) population groups itself roughly evenly into those three camps, when absent outside information it's just as reasonable to assume that the population splits itself up closer to the distribution seen in the study.
It's unreasonable to assume it is exactly equally split yes. But in a culture as highly politically charged as the present day US it isn't unreasonable to assume that political affiliation affects your social prospects and the differences aren't purely population effects.
It's open to whatever they decided to use to determine the affiliations when that stat was determined, because social "sciences" are bullshit with no real standards. But at least for data I've seen that uses registered rep, dem, or none/independent as a proxy (not ideal, but at least it's objective), men under 30 are pretty consistently >30% none/ind.