Another big problem, is that the "public faces" of SABR, guys like Keith Law & Joe Sheehan, are abrasive assholes. Nobody is going to see things your way when you are talking down to them or chastising them for being (supposedly) vapid.
Bill James wrote with a certain charm. Those who came after are nerd bullies, which is the worst kind of bully, really. Who the fuck wants to be talked down to by a cave troll hot pocket eating dickface like Joe f'n Sheehan?
Also, completely dismissing certain statistics, a Keith Law staple, loses people. Telling people the RBI is completely worthless with zero value is not only inaccurate (let's not do this again, I swear i'm not baiting anybody), but also akin to forcibly throwing somebody into a freezing pool before they've had a chance to dip their toes. There is a reason you have to leave a fish in the bag to adjust to the temperature of your aquarium as opposed to just dumping him in. When somebody is taught their entire life that the RBI is the ultimate statistic that measures a batter's worth, you aren't going to win them over be calling them stupid and dealing in absolutes like "it means absolutely nothing, do you even know what wRC+ is??".