I don't disagree with your general argument. But what type of difficulties might arise from handing down a 3-game suspension to Wirfs when you have another player on the team (Snyder) who received a one-game suspension for the same infraction just months ago? You can't really retroactively add more games to Snyder's suspension.
I also agree with
@BryceC that things ideally would be considered on a case-by-case basis, but that sure leaves the coach open to lots of outside criticism considering many of the important considerations will be known internally but not externally.