Never said he should be traded for a late 2nd, or even traded. Just that a trade should be considered given how little he sees the field.
If a first round, 9th overall, RB is healthy and gets so little playing time his 2nd season, I consider it a huge red flag. The Bills have far too many areas of need to afford to keep a first round pick on the bench in the name of "depth", particularly one that has shown so little potential thus far.
But as I said in the same post you referenced, if Gailey truly sees him as a RB of the future then keeping him is the right thing to do.