foo_mee,
I think that you are missing the point...
Head-Fi is clearly a place where a negative experience with a vendor may be voiced. That this thread has not been deleted ought to stand as testimony to that. There have been PLENTY of other threads voicing similarly negative experiences with other vendors, and the only time they end up getting locked is when a few people make it impossible to have a semi-civil discussion.
What I suspect has most people in arms in this instance is that they feel like, in fairness, some opportunity should have been extended by the OP's to the vendor to try to recify a bad situation BEFORE taking the opportunity to post about it. Things happen in business, and most agree that it's the way that things are addressed when things do happen that matters. Had this all been addressed in this manner, our erstwhile poster could present a more balanced picture.
Now, what makes this situation unusual is that more than one party is involved, neither of whom appears interested in resolving the matter...but are perfectly comfortable posting about it. I think a lot of folks feel like there is something unfair about that, and it's not unexpected that it be questioned in some manner. That happens here more than it might at other sites because of the relationship that many of our members have with our vendors - they are small operators in a closely knit industry/hobby, and make a point to get to know folks.
Now as to whether the OP may freely voice his opinion, well, I don't see where anything has been deleted. The OP has not been sanctioned for his post. He made his post, and others simply disagreed with some or other aspect of what he posted about. What it appears that you would like to see is that he be allowed to post without having that post come under scrutiny by others who may feel like he's not being completely fair to the vendor. You want the "freedom" for folks to say whatever they like without consequence or response. That's not freedom, it's opinion by fiat...
So I guess what I'm saying is that I disagree with your premise that the OP was not able "to freely just say he had a bad experience" with a vendor. He was...and that others found his basis for doing so lacking in something does not mean that he was not able to voice his opinion freely.
EDIT: Ah, I see where mbriant has made a similar point with much greater economy of words. Such is the curse I labor under.