I agree. Do the Bills usually have 6 LBs dress on gameday? If not, their whole reasoning for putting Crowell on IR is blown apart. But even if they do, I'd still prefer to waive one of the Inactive 7 instead of losing 8-14 games (probably closer to 14 than 8) of contract-year production from an established starter.
This move still strikes me as punitive and somewhat childish. Especially since Crowell is seeking a second opinion. I think the Bills assumed that the timing of Crowell's decision made it an Eff You move, and immediately struck back with an even bigger Eff You move. That will definitely hurt them in the short run, but it could go either way in the long run. I'm still very curious to hear from Crowell on this issue, because no one's gotten a quote from him since he went on IR.