Is Perception Really Reality?

When I was a young Marine in the fleet, I remember always being told that perception is reality. When I was being told that, I had the idea that maybe they were right. Perhaps if someone percieves the sky as red, it really is red, despite the fact that the rest of us see a blue sky. Though, as I moved on and saw how important it is that everyone be on the same page in an infantry fireteam, I quickly started seeing this saying as kinda subjective. 
In a Marine Corps Infantry Unit, you are required to communicate everything clearly, quickly, and with great detail. Reporting a squad sized element because you saw one guy is not excusible. Facts are all that matter on the battlefield, and this really carried over for me into the civilian world when I got retired.
When I started noticing the aggressive debates, and sometimes hateful conversations gun owners have online and in person, I quickly identified a huge disconnect between fact and perception. On one hand you have a guy who has his preference because he has used X product for a billion years, since the time he was hunting dinosaurs. He defends his continued loyalty to X product by using baseless accusations and insults to put down the other persons' preference. Now we have the other guy with Y product that he has been using for over a year, and he really believes in his product because he heard that some big name in the industry said he liked this product. He defends Y product by insulting the age of X product and its user, calling it outdated and incapable of "keeping up" with Y product. Both sides are fighting for the honors of these inanimate products without having used the other persons product thoroughly enough to judge it maturely. And this right here is where I see the huge difference between perception and reality.
For those of you who still don't get it, let me break it down for you. Just because you heard something, or think something, or want to believe something, it doesn't meant that it is true or real. The only thing that gives you any lick of credibility in this world is experience. You can not say that you don't like this or that gun because of how it felt in a shop, and then proceed to damn this gun because of this superficial evaluation. This is very common, and it is just like putting your toe in the pool water and saying that the water is freezing, yet in reality it is only 10 degrees lower in temperature than the room.