Tell me about, couldn't agree more.. but in the bullshit legal system we live with - if you say something bad, and the workshop thinks it is unfair and untruthful, they can sue you personally for slander and damage to their business.
Even if it is otherwise the truth probably in your case, how do you separate the fact from the fiction.? This is why these rules are in place, to protect your own ass being put on the line (or maybe even the forum owners). What happened if I put up "don't go to such and such" when I was just trying to bring down the name of another business simply because I was trying to sell my product. Where do you draw the line? and how do you separate genuine gripes, that to you might be bad, but to others might be "oh hum who cares he's whinging about nothing". that is what I am getting at.
An angry voice is stronger than 50 happy ones unfortunately, especially when it comes to the Internet where everybody can read it all, and often people will jump to conclusions.
Just the same if you posted in a newspaper "such and such is rubbish". If it wasn't backed with adequate facts and evidence you could be sued. Hence why you're not going to find that in the newspaper these days either.