I honestly am not sure what the OP's main point is.
In any event, except for Murray who retired due to age and Harris due to injury, all of the players on that list are still in the league and most are signed for above the vet minimum. So those aren't players who can't play - but they are players who the Bills could not for whatever reason integrate into their system. There is some kind of disconnect between the pro personnel department and the coaching staff that has persisted throughout McBeane's tenure. Offensive line (as the OP points out) is a notable exception - I am guessing because Kramer is clear at explaining what he wants and Beane and his lieutenants understand what to look for. But they struggle identifying free agent fits at nearly every other position group for reasons that frankly are confounding. It is a clear weakness of Beane and McDermott that does not seem to exist with respect to drafted rookies, whom they tend to have good plans for and a decent idea of fit/role. Not so much for free agents for whatever reason but it's a material weakness of the organization to this day. Something about their process does not work.