Though it may seem so it's actually not true - a review is classified as advertising - try putting up a cigarette review on YouTube and seen how quickly that will be purged ... Any sort of marketing is affected and reviews are just simplified marketing from a users perspective or even commercial - like magazines or alike ... Everything that promotes or influences a potential buyers decision is affected and regulated by the TPD - same reason product placements are strongly reviewed and they are not even going into details ...
Edit: at least this was how I interpreted the documents I could find so far - checking YouTube however showed there are in fact real cigarette reviews that are perfectly available ... Interesting but makes me wonder ...