Making fun of things is actually really easy if you try even a little bit. Nearly anything can be made fun of, and in practice nearly anything is made fun of. This is concerning for several reasons.
First, if you are trying to do something, whether or not people are making fun of it is not necessarily a good signal as to whether or not it's actually good. A lot of good things get made fun of. A lot of bad things get made fun of. Thus, whether or not something gets made fun of is not necessarily a good indicator of whether or not it's actually good.[1] Optimally, only bad things would get made fun of, making it easy to determine what is good and bad - but this doesn't appear to be the case.
Second, if you want to make something sound bad, it's really easy. If you don't believe this, just take a politician or organization that you like and search for some criticism of it. It should generally be trivial to find people that are making fun of it for reasons that would sound compelling to a casual observer - even if those reasons aren't actually good. But a casual observer doesn't know that and thus can easily be fooled.[2]
Further, the fact that it's easy to make fun of things makes it so that a clever person can find themselves unnecessarily contemptuous of anything and everything. This sort of premature cynicism tends to be a failure mode I've noticed in many otherwise very intelligent people. Finding faults with things is pretty trivial, but you can quickly go from "it's easy to find faults with everything" to "everything is bad." This tends to be an undesirable mode of thinking - even if true, it's not particularly helpful.
[1] Whether or not something gets made fun of by the right people is a better indicator. That said, if you know who the right people are you usually have access to much more reliable methods.
[2] If you're still not convinced, take a politician or organization that you do like and really truly try to write an argument against that politician or organization. Note that this might actually change your opinion, so be warned.
Wow. This is incredible. I am advocating sitting down, thinking critically, and asserting that warning against doing so is contrary to rationality. You're committing severe fallacies here and getting far more upvotes than I am; not reforming your own opinions without your own rationality is more popular than actually doing so.
Let's suppose you've sat down, played Devil's advocate, and decided the most logical stance is the one you've just now taken the time to realize; it is literally the best of your judgment at this exact moment. Allow me to extrapolate two illustratively extreme possibilities based on the premise of your first point:
The original opinion is the result of propaganda. You have lived your life among your peers (who are also influenced by the same propaganda) and through their opinions—or through the opinions of the ones you've liked better, or were more willing to listen to—you'd come to the conclusion that your original opinion were only natural/obvious/rational/reasonable/whatever positive description. (Let's say, hypothetically, you were of the opinion that Christianity was a useful premise to build a life around because it possesses "knowledge of God.") You sit down one day to question yourself (or God, or whatever else) and, after a bit of thinking, realize that your opinion is full of contradictions. You immediately recognize your folly and immediately consider yourself a bastion of rationality in a sea of fools. You log on to LessWrong to upvote anyone making arguments against the guy advocating the Devil (because you still believe in him) and go back to resting on your laurels, fully convinced you didn't make any other severe mistakes of rationality while you were growing up. You later donate to the anti-faith militia because really belief in God is the only real mind-killer.
The new opinion is the result of propaganda. Life is tough, and it just seems to be getting tougher. You're depressed and stressed and the idea of a psychotherapist just makes you feel like you're that much more pathetic and you'd rather not admit that to yourself. While walking across a bridge you stop for a moment to look anywhere but forward into the path that you (and so many others) have walked so many times that its worn down to a rut. You look outwards, toward the side of the bridge, trying to appreciate what else is out there. ("That I'll never be a part of," you think.) For a split second that you're barely aware of, the thought to jump off the bridge happens somewhere within your brain. You go home and within 24 hours you're standing here again. The thought it a bit stronger this time. A day in, a day out, a day in... Day in, day out, you almost unconsciously construct a barrier to prevent the through from ever reaching your consciousness. Eventually it occurs to you anyway. You instantly repulse the thought. The nearby church fails to take advantage of your situation and show you the kind of kindness that would make you instantly question if you've really been living your life correctly—a thought you didn't really need any help thinking as it is. You stare in disgust at them even more virulently than you have in every day passed. The approaching Muslim wearing a concerned look sees the disgust on your face and instantly decides now probably isn't the time to try reaching out to you. The hobo thanks you for your contribution and says, "You'll be alright man." You nod and make your way home, consciously deciding against joining his religion—whatever that is. You log on to LessWrong, ignore the warning at the bottom of the post, and decide to criticize atheism. Your mind instantly caves to the propaganda and you join the church near the bridge the next day.
If only you'd been indoctrinated in your youth and discovered that God doesn't exist in your rebellious self-forming teenager years!
Of course these are extreme examples of how propaganda can influence the opinions you form. The opinion you end up criticizing could be anything. Why, using this method, you might come to any conclusion at all, however ridiculous it is! If only future-actively-questioning-you were as intelligent as past-thinking-you!
(Votes in this comment chain as of press time: 2: 100%+, 6: 100%+, 1: 67%+, 6: 100%+. By my analysis, two people agreed with me, one disagreed, and six prefer not reforming their existing opinions.)
I had better get severely downvoted for this... Or else severely upvoted. ~__~
How can you value specific opinions over the process that generated them in the first place?!