That's because Keyword Inspector doesn't look at what's in the listing (anybody can make a tool that does that). The keywords it's using are keywords that customers are actually searching for to find the listing. That's what reverse ASIN searching does, it tells you exactly the keyword that was used to find and potentially buy that product.
Other products use the Amazon suggestion bar to find keywords to use for that listing, which is not accurate. We prefer to know exactly what customers are using to find and buy from a listing (you make more money that way).