What is your point, mass? He was named All-Pro at both positions.
As the link points out, Mack played more snaps at DE than LB this past season. Also, the Raiders recently signed Bruce Irvin.
This season he will more likely than not(yes, that was intentional) play even more snaps at DE and less snaps at LB than he did last season.
Is it unreasonable to ask that the guy be listed at the position that he actually plays the majority of the time?
Well, first let me say I agree with you 100%. He's their starting left defensive end, and I don't even know who played the 2nd most snaps at LDE for the Raiders this year. Maybe Mayowa, or Autry. Edwards/Tuck everyone else was lined up opposite him on the right side.
I'm amazed he played that many at LB, and not even sure I trust those stats. If the NFL were to ever created an EDGE position, that's where he'd be.
But fantasy web sites have to have rule, and stick with it, if they get in the business of judgement calls, their inbox would be swamped. They go by the Rotoworld, depth charts, which use the team's. I think.
This argument has been made about other players, like Suggs. However, to take the other side, this isn't a problem with Denver, why? Because Rotoworld uses a 3-4 as the base defense for them, and a 4-3 as base defense for Oakland. Von Miller's role is very, very similar to Mack's, they essentially play the exact same position. That could be a completely separate argument, about defensive alignments. Ware is a LB, and he plays DE even more than Miller or Mack, I would bet. If Mack gets listed as a DE, Miller and Ware owners should start crying foul as well.
My cynical thought is that it is in the best interest of the Raiders to list him as a LB, as franchise tags for DE is lower than LB. My guess is that you won't be seeing this change anytime soon.
So I believe this is going to be a lost cause for you.
With the positional quirks of fantasy football, my advice is to try and take advantage where you can: Find CBs that play some safety, find DTs that play a lot of DE, and accumulate as many of these new S/LB hybrids that we are seeing. My starting safeties last year were Deone Buchanon and Mark Barron. Good times.