Why do you say that?
The Jets need options at QB. Yes, they should definitely look to sign a vet before the draft. But by simply taking a BAP approach to the draft, should a QB rise to the top of their draft boards, they shouldn't hesitate to take him. And there's no reason to think a mid-rounder can't be any better than McElroy. Worst case scenario, you have four QBs battling for three spots. Not really a bad scenario.
And really, the Jets could very likely go into the draft targeting the position, and that wouldn't necessarily be all that bad, either. The only way you can get lucky with a mid-round QB is by taking one in the first place.
The QBs in this draft are terrible. Drafting one is a waste of a pick unless you're taking a flier on a guy in like the 6th.