I don't know that there is a more dangerous, common phrase in the American lexicon than "You're entitled to your own opinion." Certainly, I agree that people are free to think what they want, but people have mistaken the idea that they're allowed to hold their own opinions with the idea that they're entitled to their own set of facts. People seem to truly believe the portion of a famous Isaac Asimov quote asserting that one man's ignorance is equivalent to another man's knowledge, and this narrative is only progressed by the hyper-partisan news sources consumed by many American citizens today.
It seems today that America believes in its own subjectivity to a large extent. Conservatives have their own media sources in Fox and Breitbart, liberals have MSNBC and most of the late night entertainers and nobody has information adequate to form a well-informed, nuanced opinion on anything. People only consume news sources that affirm their own beliefs, and this just serves to further divide people into their respective bubbles. We can never move forward as a society if we continue on this path; we can't thrive as a nation if everyone is so blinded by their own ideology that they can't even agree on the facts of any situation, let alone try to reach a reasonable compromise. The United States has reached a point where even facts are relative to the individual, but there are no "liberal facts" or "conservative facts." There are only facts, and that the news tries to present them as open to interpretation and subjective based on what prior beliefs somebody holds does not make them any less true. This is the nature of reality.
Our opinions don't dictate facts, but our opinions should be shaped by facts. Anything else is insanity. We have reached a point in our political discourse where one man's ignorance is equivalent to an educated man's knowledge. Academic disciplines like economics, sociology, history, and political science are seen as subject to a person's viewpoint, but this forgets that these are disciplines in which we measure social phenomenon. Too a large degree things like poverty, education, statistics about warfare, and the economy can be measured, and though these figures are sometimes misconstrued, these studies often provide great clarity in their elucidation of the world around us. Though the information is true, there will sometimes be disagreements about the context and applications of this information, but this is not necessarily a bad thing.
Though I don't believe that there are always two reasonable, valid sides to every argument, it is certainly true that there is serious debate on some issues where both sides have good evidence to argue their point. Keynesians and classical economists both have high quality research and evidence to make reasonable points in their ongoing debate, and there are many other similar situations where both sides do make good arguments. Both sides are challenged to make their views clear and defend them, which in turn sharpens the knowledge they have of both their own and the opposing side's argument. This debate between them drives intellectual growth and learning, which is certainly something to be encouraged. The ongoing debate over relevant topics generally betters society and our understanding of the world so long as it falls within the bounds of reasonable, respectful discourse and is not applied to things that are indisputably facts.
I appreciate political debate. I enjoy reading books on different topics, and I like to learn more about economics, political science, and the outcomes shaped by the two. I think everyone should have the right to express their opinion, even if it is bordering on insane or wildly offensive, but I encourage everyone to consider whether there is reasonable evidence that supports their opinion. If there is an overwhelming scientific consensus on an issue (think climate change, vaccinations, and GMOs) and you disagree, you are wrong and your opinion is worthless. To paraphrase John Oliver, "the only accurate way to report that any significant number of people don't believe in an overwhelming scientific consensus would be to state that a poll finds that a significant number of people are wrong about something." Such things are not subject to debate or anyone's opinions because they are facts.
You are not entitled to your own facts, but you are entitled to your own opinion, which you should be able to reasonably discuss, debate, and defend at times.