Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
The jacket is very nice and very well made, however, be very careful with the sizes. I am usually a Large in any clothes I buy, but the jacket I bought was an XXL and it is just the right size. I would go at least 1 or 2 sizes bigger than you expect. Nice jacket though.