I understand your sentiment. But there's a subtle difference:
Negative feedback is not discouraged, as long as it is an honest report after the transaction is complete. For example - I order something from a vendor. They take 6 months to deliver my tarp/quilt/whatever. After I finally receive it, I post a review, addressed to the forum stating "here was my experience, here's what I thought was bad, I won't buy from them again, buyer beware". That's perfectly acceptable and encouraged, as long as it is respectful and factual.
The same thing for positive reviews, i.e. "I ordered last Friday, they were patient and super helpful on the phone, and it was waiting on my door on Monday. This vendor is awesome! Couldn't be happier!".
Both of these types of reports/reviews are accounts of how the transaction went, and your thoughts on it, and the gear, AFTER it was completed and over with.
Until the transaction is complete - that is to say either you receive your goods or you don't receive your goods and you cancel your order, get a refund, etc. - you are still in the midst of things and cannot objectively post a 'REVIEW'. And that, I think, is where the difference lies.
If you can't get a response and are worried you're not going to get your gear, call your credit card company and cancel the transaction. Or file through paypal to reverse payment, and send an email, phone call, or certified letter to the vendor saying you no longer want the goods. Then feel free to come here after that, and explain your experience in a calm, detailed way. Otherwise, take it to a private channel and keep it there.
At the end of it all, I'm not a mod. So perhaps what I say means nothing. I just think that this whole trend of using the forums as a public stage to in essence shame the vendor into replying to you by calling them out publicly for not responding is in poor taste, and contrary to what the purpose of these sub-forums seem to have been created for.