I think when I started posting on different audio boards, I cared that people recommended stuff they had obviously not heard or used. Now, I really care less. The truth is that no one is right 100% of the time, even if they have heard/used the product they love or hate. Their recommendations is only that: a recommendation, holistically, just an opinion no matter the experience. At the same time, there are some users whose opinions on very specific things, I trust without question.
Rarely, however, are these things sound 'quality' or some such metric. They are things like build quality, driveability, or the like. This is the internet where people are more fallible than they are in real life. An opinion on the internet rarely really causes you to lose face. A few apologies here and there and your avatar is back up. Made a real mistake? Well, then abandon that chia pet and make a new one.
But this is audio and there is nothing concrete. And among audiophiles, there is (as with any hyped hobby), certain aggressive tendencies to attack certain markets just because. So whether a person does or doesn't have experience with a specific product isn't my concern. It isn't my money (nor is it really any "one's" money) at stake; a recommendation, based on experience or not is just a recommendation. No one is holding a pitchfork and forcing you to buy or another person to buy. That person should have as much brains as the next 'fella' out there - that person can make the decision herself.
Now, there does need to be some policing. Internet bullying is real and can lead to problems. But you cannot take the internet out of the internet. For that reason, I agree with @Wower's post. The internet is this way. Headfi is a website about headphones. Roadbikereview is a website about road bikes. Both have their markets. Both will have fans of brand A or brand B and those fans may hate each other. Then, there will be followers who want to attain to either group and put on a show. So be it.
Whether we say that brand A is so much better in every metric than brand B and that people should not be buying brand B is of NO consequence at all. We have this one specific niche to claim as our 'expertise' but in fact, claiming that and taking on all the associated qualms and prejudices is short sighted. While we cry headphones and wear Nike shoes, another site - a big shoe site - will decry Nike. So, we are stupid by some one else's metric. The same can be said for cars, for bikes, for fishing poles, hats, boots, glasses, watches, canoes, and match sticks.
We are a community of nerds for one thing. Let's keep it that way. By pretending that our opinions about headphones are 100% accurate and biblically stern, we had better be ready to take on the fact that according to another religion, we are complete heretics.