Trying to make sense of some players ratings

Using Rick Dipietro as an example,  who has played maybe 47 NHL games in 4 yrs , & has a 75OV Rating in this league and there are many others who have ratings which are higher than they should... the guy is a shitty goaltender and lost countless games with a bad GAA and yet he's still ranked higher than guys who did better played more games, put up better numbers overall..... does this make sense to people?

Are the ratings being generated based on the sim's output or via the nhl players  real statistics? If its Sim based, then i think we should vote .. .if its nhl based on the players output/skills then guys like dipietro(who can barely walk and breathe at the same time without hurting himself) should reflect a proper rating that suits his totals etc.... same applies for other players who are overated

Maybe i missed that memo when joining the league but if i did, my apologies, might be better to re-explain again for newbies that just joined in and are wondering about the same.