If I can find three reputable sources that say the same thing, I feel pretty confident in accepting it as fact. The real trick is finding reputable sources. Media Bias Fact Check is really helpful for this.
Have you ever tried the 1 Left, 1 center, 1 right source when looking into something? I try to do this myself when I have the time and can find the articles.
How do you define the centre? Do you account for existing wide-spread social biases? E.g. systemic racism, or the neoliberal belief that we can have infinite growth on a finite planet?
They're referring to the shifting variance between political sides and the range expressed between them. The Overton Window usually.
The Overton window is the range of subjects and arguments politically acceptable to the mainstream population at a given time. It is also known as the window of discourse. The key to the concept is that the window changes over time; it can shift, or shrink or expand. It exemplifies "the slow evolution of societal values and norms".
Outside of this window you still have Left and Right, but they're the more extreme beliefs that the general populace doesn't currently accept. The window shifting over time means something that would have been considered absolutely insane 20 years ago, could be entirely mainstream now.
A current example would be federal deployment of the military to handle local protests when there is no declared State of Emergency and local government doesn't need or want assistance.
But left and right aren't absolute positions, they change in time. E.g. democrats now hold a lot of similar positions to what the republicans held in the 1980s (and also a lot of different ones).
Left and right are also a unidimensional approximation of a multidimensional value space.. E.g. most people on the left disagree with nearly everything Marjorie Taylor Greene says, but they agree with her that the US should not be supporting Israel's war on Iran.
There are also people on the left AND the right that oppose global economic liberalisation, but what is often called the "centre" supports it - clearly not a "middle" stance.
So how can you meaningfully define what is led and what is right, for the purpose of your reading?
That it also changes in time and is not absolute. And also, in many ways, that it does it does not exist (in the sense that the "centre" in one dimension might be correlated with extremes in another)
I just showed you an example of where "centre" as commonly defined is not between left and right, but opposed by both..
I guess the point is, I think those definitions are deficient, and using them as a guide to understanding what is good or true is probably a flawed methodology. It's kind of reminiscent of Fox News' old "fair and balanced" slogan (which never was, but also just missed the point of what journalism is supposed to be about, which is truth).