Well...if you're railing against false humility, sure, I agree. But it sounds like you're saying that there are truths that some people just know, those truths are of a political nature or are connected to the praxis of politics in some way (such as truths in education, medicine, ecology, etc. are so connected), but because those truths are outside the mainstream, their bearers are shouted down.
Well...again, I agree that such as that happens. Most of the ideas we accept today as true were once radical. I also agree that right now the many sides of the public discussion just aren't listening to each other, with few exceptions. At the same time, merely being outside the mainstream is no guarantee of being correct.
There are certain truths that I know, beyond the least doubt. I know that I love my wife and my daughter. I know that I exist, though as what I am uncertain. I know that there is something like a God, though It is only vaguely like anything that human beings (including this human being) can conceive. I know a few other things, but the rest are open to revision. If the mainstream is shouting people who know some truth down due to lack of humility, the proper response is not to respond in kind. Balance overcomes imbalance every. single. time. And though it may take a while, people will eventually recognize that those who are humble have done their epistemic due diligence, and will follow them.
The debates between Martin Luther and Johannes Eck are instructive in this point.