While I agree with the general point of your post, there's one area where draft capital can be misinterpreted in fantasy football: when people don't take into consideration that a WR was drafted on day two or early on day three because of their prowess as a returner. That doesn't seem to happen much for RBs, but it does with WRs all of the time. If a player profiles as a returner, and the team that drafted him needed a returner, then I'm assuming that player was picked earlier because of their skill as a returner not because of their skill as a WR.
I can't think of a good example off the top of my head, but it seems to happen about every year.