Because that's the case in 99.99% of topics, at least for me.
Additionally, what if one's education would, if honestly evaluated, conflict with widely held political views ? What if it is perceived that they may lead to policy changes ?
For instance, taking two points that are sure to be controversial here:
Among psychologists there was a long drawn-out fight about whether being shown violence (tv, video games) causes people to be more violent. That fight is over (there are extremely thorough and long duration studies available). The answer is yes, being shown violence, especially as a child, makes you more violent. Participating in violence does the same, but more so (ie. video games, and keep in mind these are decade long studies. We're talking about things like duke nukem (NON-3d version), and other ancient games, including believe it or not tetris. Not that one game was studied in isolation) (It also seems rather unclear how someone could honestly believe at this point that games like DOOM aren't worse). Participating, or being victimized, in real violence (ie. living in a bad neighbourhood) even more. Exposure to criminal acts makes people more criminal. And yes, that includes the victims.
And sometimes you ARE objectively right. Truth DOES exist.
This false equivalence that social validation is equivalent to being correct is what got us to this point.
And that's the trick to finding your own biases. Which of your beliefs are based on "social validation" rather than any notion of evidence? Which of your beliefs requires you to dismiss actual facts to the contrary?