Selected and isolated examples of individual performances are not necessarily definitive proof of an argument.
I will give you that Fenway Park benefits right handed hitters. For example, in 2012, right handed hitters in Fenway out performed right handed hitters in other parks in BA, OBP, SLG, OPS, and BiP. However, as far as homeruns by right handers go, Fenway Park trailed homerun rates per at bat in Toronto, Texas, Baltimore, Chicago (WS), and Arizona.
I will give you that one year is a selected and does not prove a point, but as former GM Theo Epstein said, “We like Fenway for left handed, opposite-field hitters more than we do for right handed pull hitters because it rewards good habits for the lefties—letting the ball travel, staying inside the ball, etc. For righties, Fenway can get you into bad habits—leaking, getting around the ball—that are tough to shake."
For the team as a whole, left-handed batters have dominated team history at Fenway Park. With a minimum of 1,000 at-bats at Fenway Park, 11 of the top 15 (and five of the top six) home batting averages in team history have been produced by left handed batters. Lefty batters Wade Boggs (.369), Ted Williams (.356), Carl Yastrzemski (.306) and even Troy O’Leary (.304) have hit better at Fenway.
Fenway is a great park for righties, but other factors are more important in determining potential players.