One of the most fundamental principles of freedom of speech is the right to make public reviews of commercial products. In pretty much every single country where there's a right to free speech (and probably even a few that don't), product reviews are an extremely protected form of speech. It doesn't matter if they are positive or negative. The idea behind this protection is, of course, pretty simple: It's a form of consumer protection. Consumers have the right to know what they are buying by being able to know about the experiences that others have had with the product. If there's some kind of flaw or negative aspect to a product, consumers have the right to know before buying. Sellers and manufacturers cannot be expected to reveal every single aspect of their product, so protecting the right of people to publish their own reviews is extremely important. Which, of course, means that in most countries a company trying to sue a reviewer for giving a negative review ...