Whenever I engage in a topical conversation or debate, one thing I considered important, vital, essential, is that you provide intelligent rationale and support your assertions with data when possible. I believe that to do anything less dilutes your credibility, be it as a writer, a politician, student, or employee.
In doing so you're giving others the opportunity to cross check your work. It's easy to make a claim:
"Player x is better than player B..."
"Franklin Roosevelt saved America from the great depression..."
"My plan will significantly reduced the costs to the taxpayer..."
But when you support that claim with clear, easy to understand evidence, you build credibility. People may disagree, they may even prove you wrong, but you've given your thoughts in clearly understandable ways. And if you have to work hard to explain your thoughts, do so. Don't treat your audience as if they aren't intelligent enough to understand. Maybe they wont, but you shouldn't assume it.
To that end, I always try to provide my readers with as much information as possible. If I say something is so, I'll try and support that with both empirical statistical evidence as well as my subjective scouting opinion. I can't promise that doing so will always ensure my correctness on a given subject, but it does mean you'll have every opportunity to tell me I'm wrong, and prove it. I'm absolutely certain that I won't always be right, and I'll also make you this promise, if I am wrong I'll always admit it.
I say all of that because it upsets me when I read articles in a newspaper or consume information from another traditional media outlet, and they fail to do so. A writer who expects me to take them on their word, is someone I struggle to respect. I don't desire to be told something is true, I desire to be shown, and I expect that I'm not entirely alone in that opinion. And if you are being speculative as a writer, or as a politician, or worker, be sure to differentiate, be clear, open, and honest.
Simply asserting something and suggesting others to take you at your word is disingenuous, and disrespectful.