His logic is that we have Coleman as our 4th receiver so bringing in a future HOF receiver with legendary locker room presence is dumb because Coleman won't get on the field as much, therefore meaning we'll be worse than last year. I think.
I still like Coleman, maybe more than a lot of fans at this point, but he didn't stand out enough last season that I would think his role should be discussed with any certainty. (Not down on him, not high on him). If Boldin joined the team and still looked like he has something left, but Coleman played well enough to make him expendable, that's a win for the team.