an overwhelming majority of citizens believe that ...

Really, the overwhelming majority of people can believe what they want, since it's not them being a judge; it is more important that the judge had been educated in this manner, and I will give my right hand that this is the case. As soon as you start an education as a judge/lawyer and related professions (even in social work), you are confronted with the bias issue and you are being made aware of it through game-cases you play through. I've done it myself in class.
It's another issue when judges ignore their own bias and work unclean in that matter. For reasons, we can think of.
But "bias" itself is a hit-term and spread around the whole internet, so you cannot say it is not a well known phenomena. It's only that people like to attribute to themselves to be not biased, but then they lie.

Keep also in mind that we live in different countries and that our legal systems differ quite a lot. For example, we don't have juries but we have the "Schöffen", instead.

In Germany and Austria, lay assessors (from the Old High German sceffino, the one who orders) are honorary judges who take part in the main proceedings of criminal trials.
As an honorary judge, the lay judge, as a representative of the people, exercises "the office of judge in full and with equal voting rights" alongside the appointed judge.
In the main hearing, lay assessors are on an equal footing with the professional judge, both in reaching a judgement and in determining the sentence.

You don't need to have an official education in law and order for that position. There are other requirements but all in all you can apply for that position as an ordinary citizen. Just for info. Most people just don't know about it. I myself didn't know.

source (not in English)