Simply because 99% of these 5 star reviews are fake reviews!
If you enjoy getting DOUBLE scammed, join up to freelancer, they will find ways to charge you for stuff you did not order and with the double chance that you will also get scammed from some freelance user.
However, If you reside in some 3rd world country, you can always get a job with freelancer that pays 15 cents/hour for writing fake reviews!
They also make you go through hoops to cancel your account. If you have a credit card or bank account listed with them, cancel asap!