It's called democracy. We assume everyone +18 has this "capacity" and as such impose the will of the majority on others. Has been going on for some decades already...
And has to deal with the issue that people in general have a strongly bad judgement owing to lack of resources to acquire the instruments (time is always relatively scarce), complicated by the fact that people in the lower side of the "distribution" of the abilities lack the awareness of their inadequacy.
Consistently, "democracy" has a strong connotation of negative value, which also implies a countervalue: "better than other systems", which does contain its big "though" - making evident that common forms are suboptimal compromises, in light of the inadequacy mentioned above.
And you did well to put 'capacity' in the bunny quotes of figurative speech, because it is a strongly false assumption.
Those "you" you refer to with that «we» should better revise their assumptions. And again you should be very wary of what you put in your head.