Sites like Tripadviser, Yelp etc. are corrupt, and this is well documented. As a business entity, if you are in good standing with these ratings sites (aka pay fees) they will filter out the bad reviews and bring positive reviews to the top of the list. The rating sites will also do the opposite, basically a blackmail scheme.
In all fairness the well documented cases of this are typically surrounding smaller businesses, so I can't speak in absolute terms for ratings of larger entities - but I can't imagine it being any different.
Anyway - posting poor reviews for a 5 star hotel on a site like tripadviser is as useful as voting for the Green Party.
GL op.