I voted yes.
The communal nature of the internet inspires debate, but I would argue that a lot of this debate ends with neither side giving up their entrenched beliefs and eventually ending in stand-off. While there is always the possibility of more information working to build a common understanding, I don't often see enough tangible results.
This is my own opinion, backed up more by my own experiences into personal forays as opposed to empirical evidence. I must confess that when it comes to flat evidence, I am shit.
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That said... It's also hard to find any medium these days that encourages debate. I feel it's rare to have a conversation where two parties are able to say to one another, "I respectfully disagree" and actually mean it. I may be a bit cynical, but I believe that political polarism is steadily creeping in no matter where you look. At least, the idea of 'I'm right, which makes you wrong' is exceedingly prevalent stateside. I'm not sure if it's the same way elsewhere.
If I had to provide a definite theory for this? I suspect a lack of empathy. If you cannot feel and understand where the other person is coming from at both a logical and emotional level when they disagree with you, then further constructive communication is a challenge. Likewise, you have to hope then that they will extend the empathy hand to use as well and that they also take the time to understand your own brand of unique reasoning. From there, it's just a matter of finding an end result that you can both agree with. Not that said end result is always going to be the prettiest thing in the world, but at least both parties would be in the know about just what they are getting into.