Those with the loudest voices usually come from those with the lesser grasp of the subject matter. What makes them more resonant is that their arguments are more simple, fewer and therefore easier to repeat and will always sound like in unison when they speak.
Unlike for those who know more, articulating would be longer and would sound in different tones that it is difficult to become a unified voice even if they are few. Sometimes a bit dragging for the majority as what appeals to most are the shorter ones. And for people who understands more, they recognize that there are a lot of things beyond their knowledge that they avoid pushing harder and would convey their positions in a calmer manner. Compared to those who have the modest cognizance to hold on to, they are more confident with it having more of those around them that approves and agrees with what they say. It's easier for them to feel that they already have everything that is needed to know about the matter and would shout about it whenever there's a chance.
But it is not always the case. Loud voices could be the good ones and the silent ones are better off not heard. So you got to listen carefully as always.