Proofs are for mathematicians, coin collectors, and distillers. In science, for example, nothing is ever proven, it's all just theories that ever-increasingly fit the observations. History is worse; it is initially written by the winners, and it takes an overwhelmingly strong appeal by non-partisans to get it corrected. This began after my school days, but even while I was being taught that Columbus discovered America I was amused that he was greeted by... people who were already here. Very often hard proof of historical reality is lacking so we do the best we can and, like science, make corrections as new evidence becomes available.
Things are getting better, but there are still a lot of people vehemently opposed to RealScience or RealHistory being taught in schools. Even some state boards of education still selectively choose books that continue to present "alternative facts," as Kellyanne famously said.