As cliched as it is, attitude makes a difference in how you view the world around you. Two people seeing the exact same thing can have vastly different views. Hell, the same person can have different views on different days or hours of the same day. Humans are like that.
To your point we literally don’t see the same things. Humans only “see” a tiny thumbnail of the world at a time even that is a blurry recreation of what reality is actually doing or happening in front of you.
It’s filling in the gaps in real time by old memories and splotched together assumptions. Now add to that other humans together in a group. You’re gonna eventually agree on a reality that you can communicate about and make decisions etc.
The internet has inserted itself in the evolutionary path of humans and inadvertently all life forms on earth. It’s like an alien entity that controls human minds like a fungus would.
The way I see it 4chan is filled with people who have untreated mental health issues. I personally have Anxiety and the world seems dark and miserable (granted im also trans and surrounded by Transphobes).
Compare LA to Phoenix AZ and you go from the description of all the things the green text says are aren't true to them being reality. 4 Chan is probably filled with people from conservative shitholes hating life because they live in a conservative shithole